gh-111650: Ensure pyconfig.h includes Py_GIL_DISABLED on Windows (GH-112778)

25 files changed, 112 insertions, 44 deletions

diff --git a/.github/workflows/reusable-windows.yml b/.github/workflows/reusable-windows.yml
index 29e0a7e..47a3c10 100644
--- a/.github/workflows/reusable-windows.yml
+++ b/.github/workflows/reusable-windows.yml
@@ -16,7 +16,7 @@ jobs:
     steps:
     - uses: actions/checkout@v4
     - name: Build CPython
-      run: .\PCbuild\build.bat -e -d -p Win32 ${{ inputs.free-threaded && '--disable-gil' || '' }}
+      run: .\PCbuild\build.bat -e -d -v -p Win32 ${{ inputs.free-threaded && '--disable-gil' || '' }}
     - name: Display build info
       run: .\python.bat -m test.pythoninfo
     - name: Tests
@@ -33,7 +33,7 @@ jobs:
     - name: Register MSVC problem matcher
       run: echo "::add-matcher::.github/problem-matchers/msvc.json"
     - name: Build CPython
-      run: .\PCbuild\build.bat -e -d -p x64 ${{ inputs.free-threaded && '--disable-gil' || '' }}
+      run: .\PCbuild\build.bat -e -d -v -p x64 ${{ inputs.free-threaded && '--disable-gil' || '' }}
     - name: Display build info
       run: .\python.bat -m test.pythoninfo
     - name: Tests
@@ -50,4 +50,4 @@ jobs:
     - name: Register MSVC problem matcher
       run: echo "::add-matcher::.github/problem-matchers/msvc.json"
     - name: Build CPython
-      run: .\PCbuild\build.bat -e -d -p arm64 ${{ inputs.free-threaded && '--disable-gil' || '' }}
+      run: .\PCbuild\build.bat -e -d -v -p arm64 ${{ inputs.free-threaded && '--disable-gil' || '' }}
diff --git a/Lib/sysconfig/__init__.py b/Lib/sysconfig/__init__.py
index 2a7fa45..c60c9f3 100644
--- a/Lib/sysconfig/__init__.py
+++ b/Lib/sysconfig/__init__.py
@@ -404,7 +404,16 @@ def get_config_h_filename():
     """Return the path of pyconfig.h."""
     if _PYTHON_BUILD:
         if os.name == "nt":
-            inc_dir = os.path.join(_PROJECT_BASE, "PC")
+            # This ought to be as simple as dirname(sys._base_executable), but
+            # if a venv uses symlinks to a build in the source tree, then this
+            # fails. So instead we guess the subdirectory name from sys.winver
+            if sys.winver.endswith('-32'):
+                arch = 'win32'
+            elif sys.winver.endswith('-arm64'):
+                arch = 'arm64'
+            else:
+                arch = 'amd64'
+            inc_dir = os.path.join(_PROJECT_BASE, 'PCbuild', arch)
         else:
             inc_dir = _PROJECT_BASE
     else:
diff --git a/Lib/test/test_sysconfig.py b/Lib/test/test_sysconfig.py
index 2a6813f..a19c04b 100644
--- a/Lib/test/test_sysconfig.py
+++ b/Lib/test/test_sysconfig.py
@@ -472,11 +472,15 @@ class TestSysConfig(unittest.TestCase):
             # should be a full source checkout.
             Python_h = os.path.join(srcdir, 'Include', 'Python.h')
             self.assertTrue(os.path.exists(Python_h), Python_h)
-            # <srcdir>/PC/pyconfig.h always exists even if unused on POSIX.
-            pyconfig_h = os.path.join(srcdir, 'PC', 'pyconfig.h')
+            # <srcdir>/PC/pyconfig.h.in always exists even if unused
+            pyconfig_h = os.path.join(srcdir, 'PC', 'pyconfig.h.in')
             self.assertTrue(os.path.exists(pyconfig_h), pyconfig_h)
             pyconfig_h_in = os.path.join(srcdir, 'pyconfig.h.in')
             self.assertTrue(os.path.exists(pyconfig_h_in), pyconfig_h_in)
+            if os.name == 'nt':
+                # <executable dir>/pyconfig.h exists on Windows in a build tree
+                pyconfig_h = os.path.join(sys.executable, '..', 'pyconfig.h')
+                self.assertTrue(os.path.exists(pyconfig_h), pyconfig_h)
         elif os.name == 'posix':
             makefile_dir = os.path.dirname(sysconfig.get_makefile_filename())
             # Issue #19340: srcdir has been realpath'ed already
diff --git a/Lib/test/test_venv.py b/Lib/test/test_venv.py
index 890672c..617d14d 100644
--- a/Lib/test/test_venv.py
+++ b/Lib/test/test_venv.py
@@ -46,14 +46,18 @@ if is_emscripten or is_wasi:
 def check_output(cmd, encoding=None):
     p = subprocess.Popen(cmd,
         stdout=subprocess.PIPE,
-        stderr=subprocess.PIPE,
-        encoding=encoding)
+        stderr=subprocess.PIPE)
     out, err = p.communicate()
     if p.returncode:
         if verbose and err:
-            print(err.decode('utf-8', 'backslashreplace'))
+            print(err.decode(encoding or 'utf-8', 'backslashreplace'))
         raise subprocess.CalledProcessError(
             p.returncode, cmd, out, err)
+    if encoding:
+        return (
+            out.decode(encoding, 'backslashreplace'),
+            err.decode(encoding, 'backslashreplace'),
+        )
     return out, err
 
 class BaseTest(unittest.TestCase):
@@ -281,8 +285,8 @@ class BasicTest(BaseTest):
             ('get_config_h_filename()', sysconfig.get_config_h_filename())):
             with self.subTest(call):
                 cmd[2] = 'import sysconfig; print(sysconfig.%s)' % call
-                out, err = check_output(cmd)
-                self.assertEqual(out.strip(), expected.encode(), err)
+                out, err = check_output(cmd, encoding='utf-8')
+                self.assertEqual(out.strip(), expected, err)
 
     @requireVenvCreate
     @unittest.skipUnless(can_symlink(), 'Needs symlinks')
@@ -303,8 +307,8 @@ class BasicTest(BaseTest):
             ('get_config_h_filename()', sysconfig.get_config_h_filename())):
             with self.subTest(call):
                 cmd[2] = 'import sysconfig; print(sysconfig.%s)' % call
-                out, err = check_output(cmd)
-                self.assertEqual(out.strip(), expected.encode(), err)
+                out, err = check_output(cmd, encoding='utf-8')
+                self.assertEqual(out.strip(), expected, err)
 
     if sys.platform == 'win32':
         ENV_SUBDIRS = (
diff --git a/Misc/NEWS.d/next/Windows/2023-12-05-22-56-30.gh-issue-111650.xlWmvM.rst b/Misc/NEWS.d/next/Windows/2023-12-05-22-56-30.gh-issue-111650.xlWmvM.rst
new file mode 100644
index 0000000..5a34933
--- /dev/null
+++ b/Misc/NEWS.d/next/Windows/2023-12-05-22-56-30.gh-issue-111650.xlWmvM.rst
@@ -0,0 +1,3 @@
+Ensures the ``Py_GIL_DISABLED`` preprocessor variable is defined in
+:file:`pyconfig.h` so that extension modules written in C are able to use
+it.
diff --git a/Modules/_ctypes/_ctypes_test.c b/Modules/_ctypes/_ctypes_test.c
index fc9fc13..2681b9c 100644
--- a/Modules/_ctypes/_ctypes_test.c
+++ b/Modules/_ctypes/_ctypes_test.c
@@ -1,6 +1,4 @@
-#ifndef _MSC_VER
 #include "pyconfig.h"   // Py_GIL_DISABLED
-#endif
 
 #ifndef Py_GIL_DISABLED
 // Need limited C API version 3.12 for Py_MOD_PER_INTERPRETER_GIL_SUPPORTED
diff --git a/Modules/_scproxy.c b/Modules/_scproxy.c
index 7920d2c..fe82e91 100644
--- a/Modules/_scproxy.c
+++ b/Modules/_scproxy.c
@@ -3,9 +3,7 @@
  * using the SystemConfiguration framework.
  */
 
-#ifndef _MSC_VER
 #include "pyconfig.h"   // Py_GIL_DISABLED
-#endif
 
 #ifndef Py_GIL_DISABLED
 // Need limited C API version 3.12 for Py_MOD_PER_INTERPRETER_GIL_SUPPORTED
diff --git a/Modules/_stat.c b/Modules/_stat.c
index 1ef1e97..80f8a92 100644
--- a/Modules/_stat.c
+++ b/Modules/_stat.c
@@ -11,9 +11,7 @@
  *
  */
 
-#ifndef _MSC_VER
 #include "pyconfig.h"   // Py_GIL_DISABLED
-#endif
 
 #ifndef Py_GIL_DISABLED
 // Need limited C API version 3.13 for PyModule_Add() on Windows
diff --git a/Modules/_testcapi/heaptype_relative.c b/Modules/_testcapi/heaptype_relative.c
index 52286f0..52bda75 100644
--- a/Modules/_testcapi/heaptype_relative.c
+++ b/Modules/_testcapi/heaptype_relative.c
@@ -1,6 +1,4 @@
-#ifndef _MSC_VER
 #include "pyconfig.h"   // Py_GIL_DISABLED
-#endif
 
 #ifndef Py_GIL_DISABLED
 #define Py_LIMITED_API 0x030c0000 // 3.12
diff --git a/Modules/_testcapi/vectorcall_limited.c b/Modules/_testcapi/vectorcall_limited.c
index 0a650f1..d7b8d33 100644
--- a/Modules/_testcapi/vectorcall_limited.c
+++ b/Modules/_testcapi/vectorcall_limited.c
@@ -1,8 +1,6 @@
 /* Test Vectorcall in the limited API */
 
-#ifndef _MSC_VER
 #include "pyconfig.h"   // Py_GIL_DISABLED
-#endif
 
 #ifndef Py_GIL_DISABLED
 #define Py_LIMITED_API 0x030c0000 // 3.12
diff --git a/Modules/_testclinic_limited.c b/Modules/_testclinic_limited.c
index 61bc841..ef595be 100644
--- a/Modules/_testclinic_limited.c
+++ b/Modules/_testclinic_limited.c
@@ -4,9 +4,7 @@
 #undef Py_BUILD_CORE_MODULE
 #undef Py_BUILD_CORE_BUILTIN
 
-#ifndef _MSC_VER
 #include "pyconfig.h"   // Py_GIL_DISABLED
-#endif
 
 #ifndef Py_GIL_DISABLED
 // For now, only limited C API 3.13 is supported
diff --git a/Modules/_testimportmultiple.c b/Modules/_testimportmultiple.c
index 245e81b..7e6556a 100644
--- a/Modules/_testimportmultiple.c
+++ b/Modules/_testimportmultiple.c
@@ -4,9 +4,7 @@
  * foo, bar), only the first one is called the same as the compiled file.
  */
 
-#ifndef _MSC_VER
 #include "pyconfig.h"   // Py_GIL_DISABLED
-#endif
 
 #ifndef Py_GIL_DISABLED
 #define Py_LIMITED_API 0x03020000
diff --git a/Modules/_uuidmodule.c b/Modules/_uuidmodule.c
index d8b211c..4b6852c 100644
--- a/Modules/_uuidmodule.c
+++ b/Modules/_uuidmodule.c
@@ -3,9 +3,7 @@
  * DCE compatible Universally Unique Identifier library.
  */
 
-#ifndef _MSC_VER
 #include "pyconfig.h"   // Py_GIL_DISABLED
-#endif
 
 #ifndef Py_GIL_DISABLED
 // Need limited C API version 3.12 for Py_MOD_PER_INTERPRETER_GIL_SUPPORTED
diff --git a/Modules/errnomodule.c b/Modules/errnomodule.c
index 8287edb..1100e9f 100644
--- a/Modules/errnomodule.c
+++ b/Modules/errnomodule.c
@@ -1,8 +1,6 @@
 /* Errno module */
 
-#ifndef _MSC_VER
 #include "pyconfig.h"   // Py_GIL_DISABLED
-#endif
 
 #ifndef Py_GIL_DISABLED
 // Need limited C API version 3.12 for Py_MOD_PER_INTERPRETER_GIL_SUPPORTED
diff --git a/Modules/resource.c b/Modules/resource.c
index a4b8f64..19020b8 100644
--- a/Modules/resource.c
+++ b/Modules/resource.c
@@ -1,6 +1,4 @@
-#ifndef _MSC_VER
 #include "pyconfig.h"   // Py_GIL_DISABLED
-#endif
 
 #ifndef Py_GIL_DISABLED
 // Need limited C API version 3.13 for PySys_Audit()
diff --git a/Modules/xxlimited.c b/Modules/xxlimited.c
index 19f6121..0bb5e12 100644
--- a/Modules/xxlimited.c
+++ b/Modules/xxlimited.c
@@ -62,9 +62,7 @@
           pass
    */
 
-#ifndef _MSC_VER
 #include "pyconfig.h"   // Py_GIL_DISABLED
-#endif
 
 #ifndef Py_GIL_DISABLED
 // Need limited C API version 3.12 for Py_MOD_PER_INTERPRETER_GIL_SUPPORTED
diff --git a/Modules/xxlimited_35.c b/Modules/xxlimited_35.c
index 867820a..754a368 100644
--- a/Modules/xxlimited_35.c
+++ b/Modules/xxlimited_35.c
@@ -5,9 +5,7 @@
  * See the xxlimited module for an extension module template.
  */
 
-#ifndef _MSC_VER
 #include "pyconfig.h"   // Py_GIL_DISABLED
-#endif
 
 #ifndef Py_GIL_DISABLED
 #define Py_LIMITED_API 0x03050000
diff --git a/PC/layout/main.py b/PC/layout/main.py
index cb2e487..accfd51 100644
--- a/PC/layout/main.py
+++ b/PC/layout/main.py
@@ -73,7 +73,10 @@ def copy_if_modified(src, dest):
         )
 
     if do_copy:
-        shutil.copy2(src, dest)
+        try:
+            shutil.copy2(src, dest)
+        except FileNotFoundError:
+            raise FileNotFoundError(src) from None
 
 
 def get_lib_layout(ns):
@@ -208,8 +211,7 @@ def get_layout(ns):
 
         for dest, src in rglob(ns.source / "Include", "**/*.h"):
             yield "include/{}".format(dest), src
-        src = ns.source / "PC" / "pyconfig.h"
-        yield "include/pyconfig.h", src
+        yield "include/pyconfig.h", ns.build / "pyconfig.h"
 
     for dest, src in get_tcltk_lib(ns):
         yield dest, src
diff --git a/PC/pyconfig.h b/PC/pyconfig.h.in
index e6b368c..d8f0a6b 100644
--- a/PC/pyconfig.h
+++ b/PC/pyconfig.h.in
@@ -739,4 +739,7 @@ Py_NO_ENABLE_SHARED to find out.  Also support MS_NO_COREDLL for b/w compat */
 /* Define if libssl has X509_VERIFY_PARAM_set1_host and related function */
 #define HAVE_X509_VERIFY_PARAM_SET1_HOST 1
 
+/* Define if you want to disable the GIL */
+#undef Py_GIL_DISABLED
+
 #endif /* !Py_CONFIG_H */
diff --git a/PC/winsound.c b/PC/winsound.c
index b0e416c..7e4ebd9 100644
--- a/PC/winsound.c
+++ b/PC/winsound.c
@@ -35,6 +35,8 @@
    winsound.PlaySound(None, 0)
 */
 
+#include "pyconfig.h"  // Py_GIL_DISABLED
+
 #ifndef Py_GIL_DISABLED
 // Need limited C API version 3.12 for Py_MOD_PER_INTERPRETER_GIL_SUPPORTED
 #define Py_LIMITED_API 0x030c0000
diff --git a/PCbuild/_freeze_module.vcxproj b/PCbuild/_freeze_module.vcxproj
index a1c37e1..f8c5faf 100644
--- a/PCbuild/_freeze_module.vcxproj
+++ b/PCbuild/_freeze_module.vcxproj
@@ -89,6 +89,7 @@
   <ItemDefinitionGroup>
     <ClCompile>
       <PreprocessorDefinitions>Py_NO_ENABLE_SHARED;Py_BUILD_CORE;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <AdditionalIncludeDirectories>$(IntDir);%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
       <Optimization>Disabled</Optimization>
       <WholeProgramOptimization>false</WholeProgramOptimization>
     </ClCompile>
@@ -258,6 +259,9 @@
     <ClCompile Include="..\Python\tracemalloc.c" />
   </ItemGroup>
   <ItemGroup>
+    <ClInclude Include="..\PC\pyconfig.h.in" />
+  </ItemGroup>
+  <ItemGroup>
     <!-- BEGIN frozen modules -->
     <None Include="..\Lib\importlib\_bootstrap.py">
       <ModName>importlib._bootstrap</ModName>
@@ -414,6 +418,32 @@
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
   <ImportGroup Label="ExtensionTargets">
   </ImportGroup>
+
+  <!-- Direct copy from pythoncore.vcxproj, but this one is only used for our
+       own build. All other extension modules will use the copy that pythoncore
+       generates. -->
+  <Target Name="_UpdatePyconfig" BeforeTargets="PrepareForBuild">
+    <MakeDir Directories="$(IntDir)" Condition="!Exists($(IntDir))" />
+    <ItemGroup>
+      <PyConfigH Remove="@(PyConfigH)" />
+      <PyConfigH Include="@(ClInclude)" Condition="'%(Filename)%(Extension)' == 'pyconfig.h.in'" />
+    </ItemGroup>
+    <Error Text="Did not find pyconfig.h" Condition="@(ClInclude) == ''" />
+    <PropertyGroup>
+      <PyConfigH>@(PyConfigH->'%(FullPath)', ';')</PyConfigH>
+      <PyConfigHText>$([System.IO.File]::ReadAllText($(PyConfigH)))</PyConfigHText>
+      <OldPyConfigH Condition="Exists('$(IntDir)pyconfig.h')">$([System.IO.File]::ReadAllText('$(IntDir)pyconfig.h'))</OldPyConfigH>
+    </PropertyGroup>
+    <PropertyGroup Condition="$(DisableGil) == 'true'">
+      <PyConfigHText>$(PyConfigHText.Replace('#undef Py_GIL_DISABLED', '#define Py_GIL_DISABLED 1'))</PyConfigHText>
+    </PropertyGroup>
+    <Message Text="Updating pyconfig.h" Condition="$(PyConfigHText.TrimEnd()) != $(OldPyConfigH.TrimEnd())" />
+    <WriteLinesToFile File="$(IntDir)pyconfig.h"
+                      Lines="$(PyConfigHText)"
+                      Overwrite="true"
+                      Condition="$(PyConfigHText.TrimEnd()) != $(OldPyConfigH.TrimEnd())" />
+  </Target>
+
   <Target Name="_RebuildGetPath" AfterTargets="_RebuildFrozen" Condition="$(Configuration) != 'PGUpdate'">
     <Exec Command='"$(TargetPath)" "%(GetPath.ModName)" "%(GetPath.FullPath)" "%(GetPath.IntFile)"' />
 
diff --git a/PCbuild/pyproject.props b/PCbuild/pyproject.props
index 0acc704..68c0550 100644
--- a/PCbuild/pyproject.props
+++ b/PCbuild/pyproject.props
@@ -10,6 +10,8 @@
     <Py_IntDir Condition="'$(Py_IntDir)' == ''">$(MSBuildThisFileDirectory)obj\</Py_IntDir>
     <IntDir>$(Py_IntDir)\$(MajorVersionNumber)$(MinorVersionNumber)$(ArchName)_$(Configuration)\$(ProjectName)\</IntDir>
     <IntDir>$(IntDir.Replace(`\\`, `\`))</IntDir>
+    <!-- pyconfig.h is updated by pythoncore.vcxproj, so it's always in pythoncore's IntDir -->
+    <GeneratedPyConfigDir>$(Py_IntDir)\$(MajorVersionNumber)$(MinorVersionNumber)$(ArchName)_$(Configuration)\pythoncore\</GeneratedPyConfigDir>
     <TargetName Condition="'$(TargetName)' == ''">$(ProjectName)</TargetName>
     <TargetName>$(TargetName)$(PyDebugExt)</TargetName>
     <GenerateManifest>false</GenerateManifest>
@@ -38,9 +40,8 @@
   </PropertyGroup>
   <ItemDefinitionGroup>
     <ClCompile>
-      <AdditionalIncludeDirectories>$(PySourcePath)Include;$(PySourcePath)Include\internal;$(PySourcePath)Include\internal\mimalloc;$(PySourcePath)PC;$(IntDir);%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
+      <AdditionalIncludeDirectories>$(PySourcePath)Include;$(PySourcePath)Include\internal;$(PySourcePath)Include\internal\mimalloc;$(GeneratedPyConfigDir);$(PySourcePath)PC;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
       <PreprocessorDefinitions>WIN32;$(_Py3NamePreprocessorDefinition);$(_PlatformPreprocessorDefinition)$(_DebugPreprocessorDefinition)$(_PydPreprocessorDefinition)%(PreprocessorDefinitions)</PreprocessorDefinitions>
-      <PreprocessorDefinitions Condition="'$(DisableGil)' == 'true'">Py_GIL_DISABLED=1;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <PreprocessorDefinitions Condition="'$(SupportPGO)' and ($(Configuration) == 'PGInstrument' or $(Configuration) == 'PGUpdate')">_Py_USING_PGO=1;%(PreprocessorDefinitions)</PreprocessorDefinitions>
 
       <Optimization>MaxSpeed</Optimization>
@@ -60,6 +61,7 @@
       <AdditionalOptions Condition="$(PlatformToolset) == 'ClangCL'">-Wno-deprecated-non-prototype -Wno-unused-label -Wno-pointer-sign -Wno-incompatible-pointer-types-discards-qualifiers -Wno-unused-function %(AdditionalOptions)</AdditionalOptions>
       <AdditionalOptions Condition="$(Configuration) != 'Debug' and $(PlatformToolset) == 'ClangCL'">-flto %(AdditionalOptions)</AdditionalOptions>
       <AdditionalOptions Condition="$(MSVCHasBrokenARM64Clamping) == 'true' and $(Platform) == 'ARM64'">-d2pattern-opt-disable:-932189325 %(AdditionalOptions)</AdditionalOptions>
+      <AdditionalOptions Condition="$(GenerateSourceDependencies) == 'true'">/sourceDependencies "$(IntDir.Trim(`\`))" %(AdditionalOptions)</AdditionalOptions>
     </ClCompile>
     <ClCompile Condition="$(Configuration) == 'Debug'">
       <InlineFunctionExpansion>OnlyExplicitInline</InlineFunctionExpansion>
diff --git a/PCbuild/pythoncore.vcxproj b/PCbuild/pythoncore.vcxproj
index 778fc83..90aa8cf 100644
--- a/PCbuild/pythoncore.vcxproj
+++ b/PCbuild/pythoncore.vcxproj
@@ -378,7 +378,7 @@
     <ClInclude Include="..\Parser\string_parser.h" />
     <ClInclude Include="..\Parser\pegen.h" />
     <ClInclude Include="..\PC\errmap.h" />
-    <ClInclude Include="..\PC\pyconfig.h" />
+    <ClInclude Include="..\PC\pyconfig.h.in" />
     <ClInclude Include="..\Python\condvar.h" />
     <ClInclude Include="..\Python\stdlib_module_names.h" />
     <ClInclude Include="..\Python\thread_nt.h" />
@@ -646,6 +646,35 @@
     <Import Project="regen.targets" />
   </ImportGroup>
   <Target Name="_TriggerRegen" BeforeTargets="PrepareForBuild" DependsOnTargets="Regen" />
+
+  <Target Name="_UpdatePyconfig" BeforeTargets="PrepareForBuild">
+    <MakeDir Directories="$(IntDir)" Condition="!Exists($(IntDir))" />
+    <ItemGroup>
+      <PyConfigH Remove="@(PyConfigH)" />
+      <PyConfigH Include="@(ClInclude)" Condition="'%(Filename)%(Extension)' == 'pyconfig.h.in'" />
+    </ItemGroup>
+    <Error Text="Did not find pyconfig.h" Condition="@(ClInclude) == ''" />
+    <PropertyGroup>
+      <PyConfigH>@(PyConfigH->'%(FullPath)', ';')</PyConfigH>
+      <PyConfigHText>$([System.IO.File]::ReadAllText($(PyConfigH)))</PyConfigHText>
+      <OldPyConfigH Condition="Exists('$(IntDir)pyconfig.h')">$([System.IO.File]::ReadAllText('$(IntDir)pyconfig.h'))</OldPyConfigH>
+    </PropertyGroup>
+    <PropertyGroup Condition="$(DisableGil) == 'true'">
+      <PyConfigHText>$(PyConfigHText.Replace('#undef Py_GIL_DISABLED', '#define Py_GIL_DISABLED 1'))</PyConfigHText>
+    </PropertyGroup>
+    <Message Text="Updating pyconfig.h" Condition="$(PyConfigHText.TrimEnd()) != $(OldPyConfigH.TrimEnd())" />
+    <WriteLinesToFile File="$(IntDir)pyconfig.h"
+                      Lines="$(PyConfigHText)"
+                      Overwrite="true"
+                      Condition="$(PyConfigHText.TrimEnd()) != $(OldPyConfigH.TrimEnd())" />
+  </Target>
+  <Target Name="_CopyPyconfig" Inputs="$(IntDir)pyconfig.h" Outputs="$(OutDir)pyconfig.h" AfterTargets="Build" DependsOnTargets="_UpdatePyconfig">
+    <Copy SourceFiles="$(IntDir)pyconfig.h" DestinationFolder="$(OutDir)" />
+  </Target>
+  <Target Name="_CleanPyconfig" AfterTargets="Clean">
+    <Delete Files="$(IntDir)pyconfig.h;$(OutDir)pyconfig.h" />
+  </Target>
+
   <Target Name="_GetBuildInfo" BeforeTargets="PrepareForBuild">
     <PropertyGroup>
       <GIT Condition="$(GIT) == ''">git</GIT>
diff --git a/Tools/msi/dev/dev_files.wxs b/Tools/msi/dev/dev_files.wxs
index 21f9c84..4357dc8 100644
--- a/Tools/msi/dev/dev_files.wxs
+++ b/Tools/msi/dev/dev_files.wxs
@@ -3,7 +3,7 @@
     <Fragment>
         <ComponentGroup Id="dev_pyconfig">
             <Component Id="include_pyconfig.h" Directory="include" Guid="*">
-                <File Id="include_pyconfig.h" Name="pyconfig.h" Source="!(bindpath.src)PC\pyconfig.h" KeyPath="yes" />
+                <File Id="include_pyconfig.h" Name="pyconfig.h" Source="pyconfig.h" KeyPath="yes" />
             </Component>
         </ComponentGroup>
     </Fragment>
diff --git a/Tools/peg_generator/pegen/build.py b/Tools/peg_generator/pegen/build.py
index 30bfb31..7df39a3 100644
--- a/Tools/peg_generator/pegen/build.py
+++ b/Tools/peg_generator/pegen/build.py
@@ -143,6 +143,10 @@ def compile_c_extension(
         str(MOD_DIR.parent.parent.parent / "Parser" / "lexer"),
         str(MOD_DIR.parent.parent.parent / "Parser" / "tokenizer"),
     ]
+    if sys.platform == "win32":
+        # HACK: The location of pyconfig.h has moved within our build, and
+        # setuptools hasn't updated for it yet. So add the path manually for now
+        include_dirs.append(pathlib.Path(sysconfig.get_config_h_filename()).parent)
     extension = Extension(
         extension_name,
         sources=[generated_source_path],