Python.patch

diff --git a/Doc/library/os.rst b/Doc/library/os.rst
index 9d206f46ae..51846163d7 100644
--- a/Doc/library/os.rst
+++ b/Doc/library/os.rst
@@ -3160,6 +3160,13 @@
 
    .. versionadded:: 3.8
 
+.. data:: allows_subprocesses
+
+   Boolean that describes whether subprocesses can be by the operating system.
+   Some platforms (e.g., iOS mobile devices) *implement* calls like
+   :func:`execv` and :func:`spawnv`, but will raise errors or break if
+   called. Calls to create subprocesses should only be invoked if
+   :data:`os.allows_subprocesses` is `True`.
 
 .. data:: MFD_CLOEXEC
           MFD_ALLOW_SEALING
diff --git a/Doc/library/subprocess.rst b/Doc/library/subprocess.rst
index 3150aa6070..d37e0d3a97 100644
--- a/Doc/library/subprocess.rst
+++ b/Doc/library/subprocess.rst
@@ -25,6 +25,11 @@
 
    :pep:`324` -- PEP proposing the subprocess module
 
+:mod:`subprocess` can only be used on platforms that support subprocess
+creation. Some platforms (especially mobile platforms) may not support
+subprocesses; if :data:`os.allows_subprocesses` is `False`, any calls in
+this module that request a subprocess be created will raise a
+:exc:`RuntimeError`.
 
 Using the :mod:`subprocess` Module
 ----------------------------------
diff --git a/Include/datetime.h b/Include/datetime.h
index 5d9f2558f9..fc66471923 100644
--- a/Include/datetime.h
+++ b/Include/datetime.h
@@ -179,7 +179,6 @@
 
 #define PyDateTime_CAPSULE_NAME "datetime.datetime_CAPI"
 
-
 /* This block is only used as part of the public API and should not be
  * included in _datetimemodule.c, which does not use the C API capsule.
  * See bpo-35081 for more details.
diff --git a/Lib/ctypes/test/test_as_parameter.py b/Lib/ctypes/test/test_as_parameter.py
index f9d27cb89d..da172b345a 100644
--- a/Lib/ctypes/test/test_as_parameter.py
+++ b/Lib/ctypes/test/test_as_parameter.py
@@ -1,9 +1,11 @@
+import os
 import unittest
 from ctypes import *
 from ctypes.test import need_symbol
 import _ctypes_test
 
-dll = CDLL(_ctypes_test.__file__)
+
+dll = CDLL(getattr(_ctypes_test, '__file__', os.environ['TEST_EXECUTABLE']))
 
 try:
     CALLBACK_FUNCTYPE = WINFUNCTYPE
diff --git a/Lib/ctypes/test/test_bitfields.py b/Lib/ctypes/test/test_bitfields.py
index 992b8c4da3..e99c3e21a2 100644
--- a/Lib/ctypes/test/test_bitfields.py
+++ b/Lib/ctypes/test/test_bitfields.py
@@ -24,7 +24,7 @@
                 ("R", c_short, 6),
                 ("S", c_short, 7)]
 
-func = CDLL(_ctypes_test.__file__).unpack_bitfields
+func = CDLL(getattr(_ctypes_test, '__file__', os.environ['TEST_EXECUTABLE'])).unpack_bitfields
 func.argtypes = POINTER(BITS), c_char
 
 ##for n in "ABCDEFGHIMNOPQRS":
diff --git a/Lib/ctypes/test/test_callbacks.py b/Lib/ctypes/test/test_callbacks.py
index d8e9c5a760..52820932b0 100644
--- a/Lib/ctypes/test/test_callbacks.py
+++ b/Lib/ctypes/test/test_callbacks.py
@@ -160,7 +160,7 @@
 
     def test_integrate(self):
         # Derived from some then non-working code, posted by David Foster
-        dll = CDLL(_ctypes_test.__file__)
+        dll = CDLL(getattr(_ctypes_test, '__file__', os.environ['TEST_EXECUTABLE']))
 
         # The function prototype called by 'integrate': double func(double);
         CALLBACK = CFUNCTYPE(c_double, c_double)
@@ -211,7 +211,7 @@
     def test_callback_register_int(self):
         # Issue #8275: buggy handling of callback args under Win64
         # NOTE: should be run on release builds as well
-        dll = CDLL(_ctypes_test.__file__)
+        dll = CDLL(getattr(_ctypes_test, '__file__', os.environ['TEST_EXECUTABLE']))
         CALLBACK = CFUNCTYPE(c_int, c_int, c_int, c_int, c_int, c_int)
         # All this function does is call the callback with its args squared
         func = dll._testfunc_cbk_reg_int
@@ -227,7 +227,7 @@
     def test_callback_register_double(self):
         # Issue #8275: buggy handling of callback args under Win64
         # NOTE: should be run on release builds as well
-        dll = CDLL(_ctypes_test.__file__)
+        dll = CDLL(getattr(_ctypes_test, '__file__', os.environ['TEST_EXECUTABLE']))
         CALLBACK = CFUNCTYPE(c_double, c_double, c_double, c_double,
                              c_double, c_double)
         # All this function does is call the callback with its args squared
diff --git a/Lib/ctypes/test/test_cfuncs.py b/Lib/ctypes/test/test_cfuncs.py
index ac2240fa19..b08b5f7581 100644
--- a/Lib/ctypes/test/test_cfuncs.py
+++ b/Lib/ctypes/test/test_cfuncs.py
@@ -1,6 +1,7 @@
 # A lot of failures in these tests on Mac OS X.
 # Byte order related?
 
+import os
 import unittest
 from ctypes import *
 from ctypes.test import need_symbol
@@ -8,7 +9,7 @@
 import _ctypes_test
 
 class CFunctions(unittest.TestCase):
-    _dll = CDLL(_ctypes_test.__file__)
+    _dll = CDLL(getattr(_ctypes_test, '__file__', os.environ['TEST_EXECUTABLE']))
 
     def S(self):
         return c_longlong.in_dll(self._dll, "last_tf_arg_s").value
@@ -206,7 +207,7 @@
 
 @need_symbol('WinDLL')
 class stdcallCFunctions(CFunctions):
-    _dll = stdcall_dll(_ctypes_test.__file__)
+    _dll = stdcall_dll(getattr(_ctypes_test, '__file__', os.environ['TEST_EXECUTABLE']))
 
 if __name__ == '__main__':
     unittest.main()
diff --git a/Lib/ctypes/test/test_checkretval.py b/Lib/ctypes/test/test_checkretval.py
index e9567dc391..3c3fbf103c 100644
--- a/Lib/ctypes/test/test_checkretval.py
+++ b/Lib/ctypes/test/test_checkretval.py
@@ -1,3 +1,4 @@
+import os
 import unittest
 
 from ctypes import *
@@ -14,7 +15,7 @@
     def test_checkretval(self):
 
         import _ctypes_test
-        dll = CDLL(_ctypes_test.__file__)
+        dll = CDLL(getattr(_ctypes_test, '__file__', os.environ['TEST_EXECUTABLE']))
         self.assertEqual(42, dll._testfunc_p_p(42))
 
         dll._testfunc_p_p.restype = CHECKED
diff --git a/Lib/ctypes/test/test_funcptr.py b/Lib/ctypes/test/test_funcptr.py
index e0b9b54e97..a5b1b55294 100644
--- a/Lib/ctypes/test/test_funcptr.py
+++ b/Lib/ctypes/test/test_funcptr.py
@@ -1,4 +1,4 @@
-import unittest
+import os, unittest
 from ctypes import *
 
 try:
@@ -8,7 +8,10 @@
     WINFUNCTYPE = CFUNCTYPE
 
 import _ctypes_test
-lib = CDLL(_ctypes_test.__file__)
+
+
+lib = CDLL(getattr(_ctypes_test, '__file__', os.environ['TEST_EXECUTABLE']))
+
 
 class CFuncPtrTestCase(unittest.TestCase):
     def test_basic(self):
diff --git a/Lib/ctypes/test/test_functions.py b/Lib/ctypes/test/test_functions.py
index 7562892420..bf8f4dc92c 100644
--- a/Lib/ctypes/test/test_functions.py
+++ b/Lib/ctypes/test/test_functions.py
@@ -7,6 +7,7 @@
 
 from ctypes import *
 from ctypes.test import need_symbol
+import os
 import sys, unittest
 
 try:
@@ -16,7 +17,9 @@
     WINFUNCTYPE = CFUNCTYPE
 
 import _ctypes_test
-dll = CDLL(_ctypes_test.__file__)
+
+
+dll = CDLL(getattr(_ctypes_test, '__file__', os.environ['TEST_EXECUTABLE']))
 if sys.platform == "win32":
     windll = WinDLL(_ctypes_test.__file__)
 
diff --git a/Lib/ctypes/test/test_libc.py b/Lib/ctypes/test/test_libc.py
index 56285b5ff8..f78a152ade 100644
--- a/Lib/ctypes/test/test_libc.py
+++ b/Lib/ctypes/test/test_libc.py
@@ -1,9 +1,12 @@
+import os
 import unittest
 
 from ctypes import *
 import _ctypes_test
 
-lib = CDLL(_ctypes_test.__file__)
+
+lib = CDLL(getattr(_ctypes_test, '__file__', os.environ['TEST_EXECUTABLE']))
+
 
 def three_way_cmp(x, y):
     """Return -1 if x < y, 0 if x == y and 1 if x > y"""
diff --git a/Lib/ctypes/test/test_parameters.py b/Lib/ctypes/test/test_parameters.py
index 38af7ac13d..db0d4986d6 100644
--- a/Lib/ctypes/test/test_parameters.py
+++ b/Lib/ctypes/test/test_parameters.py
@@ -140,7 +140,7 @@
         import _ctypes_test
         from ctypes import CDLL, c_void_p, ArgumentError
 
-        func = CDLL(_ctypes_test.__file__)._testfunc_p_p
+        func = CDLL(getattr(_ctypes_test, '__file__', os.environ['TEST_EXECUTABLE']))._testfunc_p_p
         func.restype = c_void_p
         # TypeError: has no from_param method
         self.assertRaises(TypeError, setattr, func, "argtypes", (object,))
diff --git a/Lib/ctypes/test/test_pickling.py b/Lib/ctypes/test/test_pickling.py
index c4a79b9779..833608b629 100644
--- a/Lib/ctypes/test/test_pickling.py
+++ b/Lib/ctypes/test/test_pickling.py
@@ -1,8 +1,11 @@
 import unittest
+import os
 import pickle
 from ctypes import *
 import _ctypes_test
-dll = CDLL(_ctypes_test.__file__)
+
+
+dll = CDLL(getattr(_ctypes_test, '__file__', os.environ['TEST_EXECUTABLE']))
 
 class X(Structure):
     _fields_ = [("a", c_int), ("b", c_double)]
diff --git a/Lib/ctypes/test/test_pointers.py b/Lib/ctypes/test/test_pointers.py
index e97515879f..d678be3800 100644
--- a/Lib/ctypes/test/test_pointers.py
+++ b/Lib/ctypes/test/test_pointers.py
@@ -1,3 +1,4 @@
+import os
 import unittest, sys
 
 from ctypes import *
@@ -20,7 +21,7 @@
         self.assertRaises(TypeError, A, c_ulong(33))
 
     def test_pass_pointers(self):
-        dll = CDLL(_ctypes_test.__file__)
+        dll = CDLL(getattr(_ctypes_test, '__file__', os.environ['TEST_EXECUTABLE']))
         func = dll._testfunc_p_p
         if sizeof(c_longlong) == sizeof(c_void_p):
             func.restype = c_longlong
@@ -38,7 +39,7 @@
         self.assertEqual(res[0], 12345678)
 
     def test_change_pointers(self):
-        dll = CDLL(_ctypes_test.__file__)
+        dll = CDLL(getattr(_ctypes_test, '__file__', os.environ['TEST_EXECUTABLE']))
         func = dll._testfunc_p_p
 
         i = c_int(87654)
@@ -77,7 +78,7 @@
             return 0
         callback = PROTOTYPE(func)
 
-        dll = CDLL(_ctypes_test.__file__)
+        dll = CDLL(getattr(_ctypes_test, '__file__', os.environ['TEST_EXECUTABLE']))
         # This function expects a function pointer,
         # and calls this with an integer pointer as parameter.
         # The int pointer points to a table containing the numbers 1..10
@@ -143,7 +144,7 @@
 
     def test_charpp(self):
         """Test that a character pointer-to-pointer is correctly passed"""
-        dll = CDLL(_ctypes_test.__file__)
+        dll = CDLL(getattr(_ctypes_test, '__file__', os.environ['TEST_EXECUTABLE']))
         func = dll._testfunc_c_p_p
         func.restype = c_char_p
         argv = (c_char_p * 2)()
diff --git a/Lib/ctypes/test/test_prototypes.py b/Lib/ctypes/test/test_prototypes.py
index cd0c649de3..539351f798 100644
--- a/Lib/ctypes/test/test_prototypes.py
+++ b/Lib/ctypes/test/test_prototypes.py
@@ -1,3 +1,4 @@
+import os
 from ctypes import *
 from ctypes.test import need_symbol
 import unittest
@@ -23,7 +24,9 @@
 # In this case, there would have to be an additional reference to the argument...
 
 import _ctypes_test
-testdll = CDLL(_ctypes_test.__file__)
+
+
+testdll = CDLL(getattr(_ctypes_test, '__file__', os.environ['TEST_EXECUTABLE']))
 
 # Return machine address `a` as a (possibly long) non-negative integer.
 # Starting with Python 2.5, id(anything) is always non-negative, and
diff --git a/Lib/ctypes/test/test_refcounts.py b/Lib/ctypes/test/test_refcounts.py
index f2edfa6400..0e4dd7c126 100644
--- a/Lib/ctypes/test/test_refcounts.py
+++ b/Lib/ctypes/test/test_refcounts.py
@@ -1,3 +1,4 @@
+import os
 import unittest
 from test import support
 import ctypes
@@ -7,7 +8,10 @@
 OtherCallback = ctypes.CFUNCTYPE(ctypes.c_int, ctypes.c_int, ctypes.c_ulonglong)
 
 import _ctypes_test
-dll = ctypes.CDLL(_ctypes_test.__file__)
+
+
+dll = ctypes.CDLL(getattr(_ctypes_test, '__file__', os.environ['TEST_EXECUTABLE']))
+
 
 class RefcountTestCase(unittest.TestCase):
 
diff --git a/Lib/ctypes/test/test_returnfuncptrs.py b/Lib/ctypes/test/test_returnfuncptrs.py
index 1974f40df6..7b76fae44c 100644
--- a/Lib/ctypes/test/test_returnfuncptrs.py
+++ b/Lib/ctypes/test/test_returnfuncptrs.py
@@ -1,5 +1,6 @@
 import unittest
 from ctypes import *
+import os
 
 import _ctypes_test
 
@@ -8,7 +9,7 @@
     def test_with_prototype(self):
         # The _ctypes_test shared lib/dll exports quite some functions for testing.
         # The get_strchr function returns a *pointer* to the C strchr function.
-        dll = CDLL(_ctypes_test.__file__)
+        dll = CDLL(getattr(_ctypes_test, '__file__', os.environ['TEST_EXECUTABLE']))
         get_strchr = dll.get_strchr
         get_strchr.restype = CFUNCTYPE(c_char_p, c_char_p, c_char)
         strchr = get_strchr()
@@ -20,7 +21,7 @@
         self.assertRaises(TypeError, strchr, b"abcdef")
 
     def test_without_prototype(self):
-        dll = CDLL(_ctypes_test.__file__)
+        dll = CDLL(getattr(_ctypes_test, '__file__', os.environ['TEST_EXECUTABLE']))
         get_strchr = dll.get_strchr
         # the default 'c_int' would not work on systems where sizeof(int) != sizeof(void *)
         get_strchr.restype = c_void_p
@@ -34,7 +35,7 @@
         self.assertRaises(TypeError, strchr, b"abcdef")
 
     def test_from_dll(self):
-        dll = CDLL(_ctypes_test.__file__)
+        dll = CDLL(getattr(_ctypes_test, '__file__', os.environ['TEST_EXECUTABLE']))
         # _CFuncPtr instances are now callable with a tuple argument
         # which denotes a function name and a dll:
         strchr = CFUNCTYPE(c_char_p, c_char_p, c_char)(("my_strchr", dll))
@@ -50,13 +51,13 @@
                 if key == 0:
                     return "my_strchr"
                 if key == 1:
-                    return CDLL(_ctypes_test.__file__)
+                    return CDLL(getattr(_ctypes_test, '__file__', os.environ['TEST_EXECUTABLE']))
                 raise IndexError
 
         # _CFuncPtr instances are now callable with a tuple argument
         # which denotes a function name and a dll:
         strchr = CFUNCTYPE(c_char_p, c_char_p, c_char)(
-                BadSequence(("my_strchr", CDLL(_ctypes_test.__file__))))
+                BadSequence(("my_strchr", CDLL(getattr(_ctypes_test, '__file__', os.environ['TEST_EXECUTABLE'])))))
         self.assertTrue(strchr(b"abcdef", b"b"), "bcdef")
         self.assertEqual(strchr(b"abcdef", b"x"), None)
         self.assertRaises(ArgumentError, strchr, b"abcdef", 3.0)
diff --git a/Lib/ctypes/test/test_slicing.py b/Lib/ctypes/test/test_slicing.py
index a3932f1767..6d7bfff8f2 100644
--- a/Lib/ctypes/test/test_slicing.py
+++ b/Lib/ctypes/test/test_slicing.py
@@ -1,3 +1,4 @@
+import os
 import unittest
 from ctypes import *
 from ctypes.test import need_symbol
@@ -62,7 +63,7 @@
     def test_char_ptr(self):
         s = b"abcdefghijklmnopqrstuvwxyz"
 
-        dll = CDLL(_ctypes_test.__file__)
+        dll = CDLL(getattr(_ctypes_test, '__file__', os.environ['TEST_EXECUTABLE']))
         dll.my_strdup.restype = POINTER(c_char)
         dll.my_free.restype = None
         res = dll.my_strdup(s)
@@ -94,7 +95,7 @@
         dll.my_free(res)
 
     def test_char_ptr_with_free(self):
-        dll = CDLL(_ctypes_test.__file__)
+        dll = CDLL(getattr(_ctypes_test, '__file__', os.environ['TEST_EXECUTABLE']))
         s = b"abcdefghijklmnopqrstuvwxyz"
 
         class allocated_c_char_p(c_char_p):
@@ -130,7 +131,7 @@
     def test_wchar_ptr(self):
         s = "abcdefghijklmnopqrstuvwxyz\0"
 
-        dll = CDLL(_ctypes_test.__file__)
+        dll = CDLL(getattr(_ctypes_test, '__file__', os.environ['TEST_EXECUTABLE']))
         dll.my_wcsdup.restype = POINTER(c_wchar)
         dll.my_wcsdup.argtypes = POINTER(c_wchar),
         dll.my_free.restype = None
diff --git a/Lib/ctypes/test/test_stringptr.py b/Lib/ctypes/test/test_stringptr.py
index c20951f4ce..fde0eef1c7 100644
--- a/Lib/ctypes/test/test_stringptr.py
+++ b/Lib/ctypes/test/test_stringptr.py
@@ -1,10 +1,12 @@
+import os
 import unittest
 from test import support
 from ctypes import *
 
 import _ctypes_test
 
-lib = CDLL(_ctypes_test.__file__)
+
+lib = CDLL(getattr(_ctypes_test, '__file__', os.environ['TEST_EXECUTABLE']))
 
 class StringPtrTestCase(unittest.TestCase):
 
diff --git a/Lib/ctypes/test/test_unicode.py b/Lib/ctypes/test/test_unicode.py
index c200af7b65..ea3945d56b 100644
--- a/Lib/ctypes/test/test_unicode.py
+++ b/Lib/ctypes/test/test_unicode.py
@@ -1,3 +1,4 @@
+import os
 import unittest
 import ctypes
 from ctypes.test import need_symbol
@@ -7,7 +8,7 @@
 @need_symbol('c_wchar')
 class UnicodeTestCase(unittest.TestCase):
     def test_wcslen(self):
-        dll = ctypes.CDLL(_ctypes_test.__file__)
+        dll = ctypes.CDLL(getattr(_ctypes_test, '__file__', os.environ['TEST_EXECUTABLE']))
         wcslen = dll.my_wcslen
         wcslen.argtypes = [ctypes.c_wchar_p]
 
@@ -26,7 +27,7 @@
         self.assertEqual(buf[::2], 'a\xe4\xfc')
         self.assertEqual(buf[6:5:-1], "")
 
-func = ctypes.CDLL(_ctypes_test.__file__)._testfunc_p_p
+func = ctypes.CDLL(getattr(_ctypes_test, '__file__', os.environ['TEST_EXECUTABLE']))._testfunc_p_p
 
 class StringTestCase(UnicodeTestCase):
     def setUp(self):
diff --git a/Lib/ctypes/test/test_values.py b/Lib/ctypes/test/test_values.py
index 87eb9198ad..e40b82506f 100644
--- a/Lib/ctypes/test/test_values.py
+++ b/Lib/ctypes/test/test_values.py
@@ -2,6 +2,7 @@
 A testcase which accesses *values* in a dll.
 """
 
+import os
 import unittest
 import sys
 from ctypes import *
@@ -13,7 +14,7 @@
     def test_an_integer(self):
         # This test checks and changes an integer stored inside the
         # _ctypes_test dll/shared lib.
-        ctdll = CDLL(_ctypes_test.__file__)
+        ctdll = CDLL(getattr(_ctypes_test, '__file__', os.environ['TEST_EXECUTABLE']))
         an_integer = c_int.in_dll(ctdll, "an_integer")
         x = an_integer.value
         self.assertEqual(x, ctdll.get_an_integer())
@@ -25,7 +26,7 @@
         self.assertEqual(x, ctdll.get_an_integer())
 
     def test_undefined(self):
-        ctdll = CDLL(_ctypes_test.__file__)
+        ctdll = CDLL(getattr(_ctypes_test, '__file__', os.environ['TEST_EXECUTABLE']))
         self.assertRaises(ValueError, c_int.in_dll, ctdll, "Undefined_Symbol")
 
 class PythonValuesTestCase(unittest.TestCase):
diff --git a/Lib/ctypes/test/test_win32.py b/Lib/ctypes/test/test_win32.py
index e51bdc8ad6..78ba8e6786 100644
--- a/Lib/ctypes/test/test_win32.py
+++ b/Lib/ctypes/test/test_win32.py
@@ -1,6 +1,7 @@
 # Windows specific tests
 
 from ctypes import *
+import os
 import unittest, sys
 from test import support
 
@@ -102,7 +103,7 @@
                         ("right", c_long),
                         ("bottom", c_long)]
 
-        dll = CDLL(_ctypes_test.__file__)
+        dll = CDLL(getattr(_ctypes_test, '__file__', os.environ['TEST_EXECUTABLE']))
 
         pt = POINT(15, 25)
         left = c_long.in_dll(dll, 'left')
diff --git a/Lib/ctypes/util.py b/Lib/ctypes/util.py
index 0c2510e161..6c3c43f11d 100644
--- a/Lib/ctypes/util.py
+++ b/Lib/ctypes/util.py
@@ -67,7 +67,7 @@
                 return fname
         return None
 
-elif os.name == "posix" and sys.platform == "darwin":
+elif os.name == "posix" and sys.platform in ('darwin', 'ios', 'tvos', 'watchos'):
     from ctypes.macholib.dyld import dyld_find as _dyld_find
     def find_library(name):
         possible = ['lib%s.dylib' % name,
diff --git a/Lib/distutils/tests/test_build_ext.py b/Lib/distutils/tests/test_build_ext.py
index 808c0dc287..b4813efe0c 100644
--- a/Lib/distutils/tests/test_build_ext.py
+++ b/Lib/distutils/tests/test_build_ext.py
@@ -52,6 +52,8 @@
     def build_ext(self, *args, **kwargs):
         return build_ext(*args, **kwargs)
 
+    @unittest.skipUnless(os.name == 'nt' or (os.name == 'posix' and hasattr(os, 'fork') and os.allows_subprocesses),
+                         "distutils cannot spawn child processes")
     def test_build_ext(self):
         cmd = support.missing_compiler_executable()
         if cmd is not None:
@@ -328,6 +330,8 @@
         cmd.run()
         self.assertEqual(cmd.compiler, 'unix')
 
+    @unittest.skipUnless(os.name == 'nt' or (os.name == 'posix' and hasattr(os, 'fork') and os.allows_subprocesses),
+                         "distutils cannot spawn child processes")
     def test_get_outputs(self):
         cmd = support.missing_compiler_executable()
         if cmd is not None:
diff --git a/Lib/distutils/tests/test_build_py.py b/Lib/distutils/tests/test_build_py.py
index 0712e92c6a..52a0121250 100644
--- a/Lib/distutils/tests/test_build_py.py
+++ b/Lib/distutils/tests/test_build_py.py
@@ -106,6 +106,8 @@
                          ['boiledeggs.%s.pyc' % sys.implementation.cache_tag])
 
     @unittest.skipIf(sys.dont_write_bytecode, 'byte-compile disabled')
+    @unittest.skipUnless(os.name == 'nt' or (os.name == 'posix' and hasattr(os, 'fork') and os.allows_subprocesses),
+                         "distutils cannot spawn child processes")
     def test_byte_compile_optimized(self):
         project_dir, dist = self.create_dist(py_modules=['boiledeggs'])
         os.chdir(project_dir)
diff --git a/Lib/distutils/tests/test_config_cmd.py b/Lib/distutils/tests/test_config_cmd.py
index 9aeab07b46..3c6dfc0439 100644
--- a/Lib/distutils/tests/test_config_cmd.py
+++ b/Lib/distutils/tests/test_config_cmd.py
@@ -38,6 +38,7 @@
         self.assertEqual(len(self._logs), numlines+1)
 
     @unittest.skipIf(sys.platform == 'win32', "can't test on Windows")
+    @unittest.skipUnless(os.allows_subprocesses, 'Test requires support for subprocesses.')
     def test_search_cpp(self):
         cmd = missing_compiler_executable(['preprocessor'])
         if cmd is not None:
diff --git a/Lib/distutils/tests/test_cygwinccompiler.py b/Lib/distutils/tests/test_cygwinccompiler.py
index 9dc869de4c..176a87f8a8 100644
--- a/Lib/distutils/tests/test_cygwinccompiler.py
+++ b/Lib/distutils/tests/test_cygwinccompiler.py
@@ -5,11 +5,14 @@
 from io import BytesIO
 from test.support import run_unittest
 
-from distutils import cygwinccompiler
-from distutils.cygwinccompiler import (check_config_h,
-                                       CONFIG_H_OK, CONFIG_H_NOTOK,
-                                       CONFIG_H_UNCERTAIN, get_versions,
-                                       get_msvcr)
+# Importing cygwinccompiler attempts to import other tools
+# that may not exist unless you're on win32.
+if sys.platform == 'win32':
+    from distutils import cygwinccompiler
+    from distutils.cygwinccompiler import (check_config_h,
+                                           CONFIG_H_OK, CONFIG_H_NOTOK,
+                                           CONFIG_H_UNCERTAIN, get_versions,
+                                           get_msvcr)
 from distutils.tests import support
 
 class FakePopen(object):
@@ -25,6 +28,7 @@
             self.stdout = os.popen(cmd, 'r')
 
 
+@unittest.skipUnless(sys.platform == "win32", "These tests are only for win32")
 class CygwinCCompilerTestCase(support.TempdirManager,
                               unittest.TestCase):
 
@@ -118,7 +122,7 @@
     def test_get_msvcr(self):
 
         # none
-        sys.version  = ('2.6.1 (r261:67515, Dec  6 2008, 16:42:21) '
+        sys.version = ('2.6.1 (r261:67515, Dec  6 2008, 16:42:21) '
                         '\n[GCC 4.0.1 (Apple Computer, Inc. build 5370)]')
         self.assertEqual(get_msvcr(), None)
 
diff --git a/Lib/distutils/tests/test_install.py b/Lib/distutils/tests/test_install.py
index 51c80e0421..11008da5f2 100644
--- a/Lib/distutils/tests/test_install.py
+++ b/Lib/distutils/tests/test_install.py
@@ -197,6 +197,8 @@
                     'UNKNOWN-0.0.0-py%s.%s.egg-info' % sys.version_info[:2]]
         self.assertEqual(found, expected)
 
+    @unittest.skipUnless(os.name == 'nt' or (os.name == 'posix' and hasattr(os, 'fork') and os.allows_subprocesses),
+                         "distutils cannot spawn child processes")
     def test_record_extensions(self):
         cmd = test_support.missing_compiler_executable()
         if cmd is not None:
diff --git a/Lib/distutils/tests/test_install_lib.py b/Lib/distutils/tests/test_install_lib.py
index fda6315bbc..63c71a8d46 100644
--- a/Lib/distutils/tests/test_install_lib.py
+++ b/Lib/distutils/tests/test_install_lib.py
@@ -35,6 +35,8 @@
         self.assertEqual(cmd.optimize, 2)
 
     @unittest.skipIf(sys.dont_write_bytecode, 'byte-compile disabled')
+    @unittest.skipUnless(os.name == 'nt' or (os.name == 'posix' and hasattr(os, 'fork') and os.allows_subprocesses),
+                         "distutils cannot spawn child processes")
     def test_byte_compile(self):
         project_dir, dist = self.create_dist()
         os.chdir(project_dir)
diff --git a/Lib/distutils/tests/test_spawn.py b/Lib/distutils/tests/test_spawn.py
index ad5038142f..856afe86c1 100644
--- a/Lib/distutils/tests/test_spawn.py
+++ b/Lib/distutils/tests/test_spawn.py
@@ -15,8 +15,8 @@
                     support.LoggingSilencer,
                     unittest.TestCase):
 
-    @unittest.skipUnless(os.name in ('nt', 'posix'),
-                         'Runs only under posix or nt')
+    @unittest.skipUnless(os.name == 'nt' or (os.name == 'posix' and hasattr(os, 'fork') and os.allows_subprocesses),
+                         "distutils cannot spawn child processes")
     def test_spawn(self):
         tmpdir = self.mkdtemp()
 
diff --git a/Lib/distutils/tests/test_sysconfig.py b/Lib/distutils/tests/test_sysconfig.py
index 236755d095..721bc91093 100644
--- a/Lib/distutils/tests/test_sysconfig.py
+++ b/Lib/distutils/tests/test_sysconfig.py
@@ -244,6 +244,7 @@
         self.assertIsNotNone(vars['SO'])
         self.assertEqual(vars['SO'], vars['EXT_SUFFIX'])
 
+    @unittest.skipUnless(os.allows_subprocesses, 'Test requires support for subprocesses.')
     def test_customize_compiler_before_get_config_vars(self):
         # Issue #21923: test that a Distribution compiler
         # instance can be called without an explicit call to
diff --git a/Lib/distutils/tests/test_util.py b/Lib/distutils/tests/test_util.py
index bf0d4333f9..09ba51bcea 100644
--- a/Lib/distutils/tests/test_util.py
+++ b/Lib/distutils/tests/test_util.py
@@ -233,6 +233,8 @@
 
         # XXX platforms to be covered: mac
 
+    @unittest.skipUnless(os.name == 'nt' or (os.name == 'posix' and hasattr(os, 'fork') and os.allows_subprocesses),
+                         "distutils cannot spawn child processes")
     def test_check_environ(self):
         util._environ_checked = 0
         os.environ.pop('HOME', None)
diff --git a/Lib/importlib/_bootstrap_external.py b/Lib/importlib/_bootstrap_external.py
index 25a3f8c0e0..560307ffad 100644
--- a/Lib/importlib/_bootstrap_external.py
+++ b/Lib/importlib/_bootstrap_external.py
@@ -21,7 +21,7 @@
 
 # Bootstrap-related code ######################################################
 _CASE_INSENSITIVE_PLATFORMS_STR_KEY = 'win',
-_CASE_INSENSITIVE_PLATFORMS_BYTES_KEY = 'cygwin', 'darwin'
+_CASE_INSENSITIVE_PLATFORMS_BYTES_KEY = 'cygwin', 'darwin', 'ios', 'tvos', 'watchos'
 _CASE_INSENSITIVE_PLATFORMS =  (_CASE_INSENSITIVE_PLATFORMS_BYTES_KEY
                                 + _CASE_INSENSITIVE_PLATFORMS_STR_KEY)
 
diff --git a/Lib/os.py b/Lib/os.py
index b794159f86..449cf932b6 100644
--- a/Lib/os.py
+++ b/Lib/os.py
@@ -36,7 +36,7 @@
 __all__ = ["altsep", "curdir", "pardir", "sep", "pathsep", "linesep",
            "defpath", "name", "path", "devnull", "SEEK_SET", "SEEK_CUR",
            "SEEK_END", "fsencode", "fsdecode", "get_exec_path", "fdopen",
-           "popen", "extsep"]
+           "popen", "extsep", "allows_subprocesses"]
 
 def _exists(name):
     return name in globals()
@@ -830,6 +830,13 @@
 fsencode, fsdecode = _fscodec()
 del _fscodec
 
+
+if sys.platform in ('iOS', 'tvos', 'watchos'):
+    allows_subprocesses = False
+else:
+    allows_subprocesses = True
+
+
 # Supply spawn*() (probably only for Unix)
 if _exists("fork") and not _exists("spawnv") and _exists("execv"):
 
diff --git a/Lib/platform.py b/Lib/platform.py
index 6258827d0e..af32c6c70c 100755
--- a/Lib/platform.py
+++ b/Lib/platform.py
@@ -613,7 +613,7 @@
         default in case the command should fail.
 
     """
-    if sys.platform in ('dos', 'win32', 'win16'):
+    if sys.platform in ('dos', 'win32', 'win16', 'ios', 'tvos', 'watchos'):
         # XXX Others too ?
         return default
 
diff --git a/Lib/site.py b/Lib/site.py
index 9e617afb00..41305298d3 100644
--- a/Lib/site.py
+++ b/Lib/site.py
@@ -271,6 +271,9 @@
 
     if sys.platform == 'darwin' and sys._framework:
         return f'{userbase}/lib/python/site-packages'
+    elif sys.platform in ('ios', 'tvos', 'watchos'):
+        from sysconfig import get_path
+        return get_path('purelib', sys.platform)
 
     return f'{userbase}/lib/python{version[0]}.{version[1]}/site-packages'
 
diff --git a/Lib/subprocess.py b/Lib/subprocess.py
index 0311e3a1f8..ca01e9aa16 100644
--- a/Lib/subprocess.py
+++ b/Lib/subprocess.py
@@ -762,6 +762,9 @@
                  pass_fds=(), *, user=None, group=None, extra_groups=None,
                  encoding=None, errors=None, text=None, umask=-1):
         """Create new Popen instance."""
+        if not os.allows_subprocesses:
+            raise RuntimeError("Subprocesses are not supported on this platform.")
+
         _cleanup()
         # Held while anything is calling waitpid before returncode has been
         # updated to prevent clobbering returncode if wait() or poll() are
@@ -1834,7 +1837,7 @@
             else:
                 self.returncode = waitstatus_to_exitcode(sts)
 
-        def _internal_poll(self, _deadstate=None, _waitpid=os.waitpid,
+        def _internal_poll(self, _deadstate=None, _waitpid=None,
                 _WNOHANG=os.WNOHANG, _ECHILD=errno.ECHILD):
             """Check if child process has terminated.  Returns returncode
             attribute.
@@ -1843,6 +1846,8 @@
             outside of the local scope (nor can any methods it calls).
 
             """
+            if _waitpid is None:
+                _waitpid = os.waitpid
             if self.returncode is None:
                 if not self._waitpid_lock.acquire(False):
                     # Something else is busy calling waitpid.  Don't allow two
diff --git a/Lib/sysconfig.py b/Lib/sysconfig.py
index e3f79bfde5..2850eaeb5e 100644
--- a/Lib/sysconfig.py
+++ b/Lib/sysconfig.py
@@ -84,6 +84,33 @@
         'scripts': '{userbase}/bin',
         'data': '{userbase}',
         },
+    'ios': {
+        'stdlib': '{installed_base}/lib/python%s' % sys.version[:3],
+        'platstdlib': '{installed_base}/lib/python%s' % sys.version[:3],
+        'purelib': '{installed_base}/lib/python%s/site-packages' % sys.version[:3],
+        'platlib': '{installed_base}/lib/python%s/site-packages' % sys.version[:3],
+        'include': '{installed_base}/include',
+        'scripts': '{installed_base}/bin',
+        'data': '{installed_base}/Resources',
+        },
+    'tvos': {
+        'stdlib': '{installed_base}/lib/python%s' % sys.version[:3],
+        'platstdlib': '{installed_base}/lib/python%s' % sys.version[:3],
+        'purelib': '{installed_base}/lib/python%s/site-packages' % sys.version[:3],
+        'platlib': '{installed_base}/lib/python%s/site-packages' % sys.version[:3],
+        'include': '{installed_base}/include',
+        'scripts': '{installed_base}/bin',
+        'data': '{installed_base}/Resources',
+        },
+    'watchos': {
+        'stdlib': '{installed_base}/lib/python%s' % sys.version[:3],
+        'platstdlib': '{installed_base}/lib/python%s' % sys.version[:3],
+        'purelib': '{installed_base}/lib/python%s/site-packages' % sys.version[:3],
+        'platlib': '{installed_base}/lib/python%s/site-packages' % sys.version[:3],
+        'include': '{installed_base}/include',
+        'scripts': '{installed_base}/bin',
+        'data': '{installed_base}/Resources',
+        },
     }
 
 _SCHEME_KEYS = ('stdlib', 'platstdlib', 'purelib', 'platlib', 'include',
@@ -185,6 +212,8 @@
     if os.name == 'posix':
         # the default scheme for posix is posix_prefix
         return 'posix_prefix'
+    elif sys.platform in ('ios', 'tvos', 'watchos'):
+        return sys.platform
     return os.name
 
 
@@ -205,6 +234,11 @@
     if sys.platform == "darwin" and sys._framework:
         return joinuser("~", "Library", sys._framework,
                         "%d.%d" % sys.version_info[:2])
+    elif sys.platform in ('ios', 'tvos', 'watchos'):
+        if env_base:
+            return env_base
+        else:
+            return _BASE_PREFIX
 
     return joinuser("~", ".local")
 
diff --git a/Lib/test/support/__init__.py b/Lib/test/support/__init__.py
index aee3737ffc..b7060d9d1a 100644
--- a/Lib/test/support/__init__.py
+++ b/Lib/test/support/__init__.py
@@ -782,8 +782,8 @@
 
 # TESTFN_UNICODE is a non-ascii filename
 TESTFN_UNICODE = TESTFN_ASCII + "-\xe0\xf2\u0258\u0141\u011f"
-if sys.platform == 'darwin':
-    # In Mac OS X's VFS API file names are, by definition, canonically
+if sys.platform in ('darwin', 'ios', 'tvos', 'watchos'):
+    # In iOS and Mac OS X, VFS API file names are, by definition, canonically
     # decomposed Unicode, encoded using UTF-8. See QA1173:
     # http://developer.apple.com/mac/library/qa/qa2001/qa1173.html
     import unicodedata
@@ -809,8 +809,8 @@
                   'Unicode filename tests may not be effective'
                   % (TESTFN_UNENCODABLE, TESTFN_ENCODING))
             TESTFN_UNENCODABLE = None
-# Mac OS X denies unencodable filenames (invalid utf-8)
-elif sys.platform != 'darwin':
+# Mac OS X and iOS deny unencodable filenames (invalid utf-8)
+elif sys.platform not in ('darwin', 'ios', 'tvos', 'watchos'):
     try:
         # ascii and utf-8 cannot encode the byte 0xff
         b'\xff'.decode(TESTFN_ENCODING)
diff --git a/Lib/test/support/script_helper.py b/Lib/test/support/script_helper.py
index 37e576d4a7..1d7176bf13 100644
--- a/Lib/test/support/script_helper.py
+++ b/Lib/test/support/script_helper.py
@@ -8,6 +8,7 @@
 import os.path
 import subprocess
 import py_compile
+import unittest
 import zipfile
 
 from importlib.util import source_from_cache
@@ -17,6 +18,8 @@
 # Cached result of the expensive test performed in the function below.
 __cached_interp_requires_environment = None
 
+
+@unittest.skipUnless(os.allows_subprocesses, 'Test requires support for subprocesses.')
 def interpreter_requires_environment():
     """
     Returns True if our sys.executable interpreter requires environment
@@ -136,6 +139,7 @@
     rc = proc.returncode
     return _PythonRunResult(rc, out, err), cmd_line
 
+@unittest.skipUnless(os.allows_subprocesses, 'Test requires support for subprocesses.')
 def _assert_python(expected_success, /, *args, **env_vars):
     res, cmd_line = run_python_until_end(*args, **env_vars)
     if (res.rc and expected_success) or (not res.rc and not expected_success):
@@ -165,6 +169,8 @@
     """
     return _assert_python(False, *args, **env_vars)
 
+
+@unittest.skipUnless(os.allows_subprocesses, 'Test requires support for subprocesses.')
 def spawn_python(*args, stdout=subprocess.PIPE, stderr=subprocess.STDOUT, **kw):
     """Run a Python subprocess with the given arguments.
 
diff --git a/Lib/test/test_asyncio/test_events.py b/Lib/test/test_asyncio/test_events.py
index fa6c49d89d..1e3db27552 100644
--- a/Lib/test/test_asyncio/test_events.py
+++ b/Lib/test/test_asyncio/test_events.py
@@ -516,6 +516,8 @@
             self._basetest_create_connection(conn_fut)
 
     @socket_helper.skip_unless_bind_unix_socket
+    @unittest.skipIf(sys.platform in ('ios', 'tvos', 'watchos'),
+                     "%s doesn't fully support UNIX sockets." % sys.platform)
     def test_create_unix_connection(self):
         # Issue #20682: On Mac OS X Tiger, getsockname() returns a
         # zero-length address for UNIX socket.
@@ -608,6 +610,8 @@
         self.assertEqual(cm.exception.reason, 'CERTIFICATE_VERIFY_FAILED')
 
     @unittest.skipIf(ssl is None, 'No ssl module')
+    @unittest.skipIf(sys.platform in ('ios', 'tvos', 'watchos'),
+                     "%s doesn't fully support UNIX sockets." % sys.platform)
     def test_create_ssl_connection(self):
         with test_utils.run_test_server(use_ssl=True) as httpd:
             create_connection = functools.partial(
@@ -619,6 +623,8 @@
 
     @socket_helper.skip_unless_bind_unix_socket
     @unittest.skipIf(ssl is None, 'No ssl module')
+    @unittest.skipIf(sys.platform in ('ios', 'tvos', 'watchos'),
+                     "%s doesn't fully support UNIX sockets." % sys.platform)
     def test_create_ssl_unix_connection(self):
         # Issue #20682: On Mac OS X Tiger, getsockname() returns a
         # zero-length address for UNIX socket.
@@ -842,6 +848,8 @@
         return server, path
 
     @socket_helper.skip_unless_bind_unix_socket
+    @unittest.skipIf(sys.platform in ('ios', 'tvos', 'watchos'),
+                     "%s doesn't fully support UNIX sockets." % sys.platform)
     def test_create_unix_server(self):
         proto = MyProto(loop=self.loop)
         server, path = self._make_unix_server(lambda: proto)
@@ -870,6 +878,8 @@
         server.close()
 
     @unittest.skipUnless(hasattr(socket, 'AF_UNIX'), 'No UNIX Sockets')
+    @unittest.skipIf(sys.platform in ('ios', 'tvos', 'watchos'),
+                     "%s doesn't fully support UNIX sockets." % sys.platform)
     def test_create_unix_server_path_socket_error(self):
         proto = MyProto(loop=self.loop)
         sock = socket.socket()
@@ -935,6 +945,8 @@
 
     @socket_helper.skip_unless_bind_unix_socket
     @unittest.skipIf(ssl is None, 'No ssl module')
+    @unittest.skipIf(sys.platform in ('ios', 'tvos', 'watchos'),
+                     "%s doesn't fully support UNIX sockets." % sys.platform)
     def test_create_unix_server_ssl(self):
         proto = MyProto(loop=self.loop)
         server, path = self._make_ssl_unix_server(
@@ -965,6 +977,8 @@
         server.close()
 
     @unittest.skipIf(ssl is None, 'No ssl module')
+    @unittest.skipIf(sys.platform in ('ios', 'tvos', 'watchos'),
+                     "%s doesn't fully support UNIX sockets." % sys.platform)
     def test_create_server_ssl_verify_failed(self):
         proto = MyProto(loop=self.loop)
         server, host, port = self._make_ssl_server(
@@ -995,6 +1009,8 @@
 
     @socket_helper.skip_unless_bind_unix_socket
     @unittest.skipIf(ssl is None, 'No ssl module')
+    @unittest.skipIf(sys.platform in ('ios', 'tvos', 'watchos'),
+                     "%s doesn't fully support UNIX sockets." % sys.platform)
     def test_create_unix_server_ssl_verify_failed(self):
         proto = MyProto(loop=self.loop)
         server, path = self._make_ssl_unix_server(
@@ -1055,6 +1071,8 @@
 
     @socket_helper.skip_unless_bind_unix_socket
     @unittest.skipIf(ssl is None, 'No ssl module')
+    @unittest.skipIf(sys.platform in ('ios', 'tvos', 'watchos'),
+                     "%s doesn't fully support UNIX sockets." % sys.platform)
     def test_create_unix_server_ssl_verified(self):
         proto = MyProto(loop=self.loop)
         server, path = self._make_ssl_unix_server(
@@ -1714,6 +1732,7 @@
             next(it)
 
 
+@unittest.skipUnless(os.allows_subprocesses, 'Test requires support for subprocesses.')
 class SubprocessTestsMixin: