Issue #15431: Add _freeze_importlib project to regenerate importlib.h on Windows.
Patch by Kristján Valur Jónsson.
diff --git a/PCbuild/pcbuild.sln b/PCbuild/pcbuild.sln
index 327757e..ee39e17 100644
--- a/PCbuild/pcbuild.sln
+++ b/PCbuild/pcbuild.sln
@@ -72,6 +72,8 @@
 EndProject

 Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "pywlauncher", "pywlauncher.vcxproj", "{1D4B18D3-7C12-4ECB-9179-8531FF876CE6}"

 EndProject

+Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "_freeze_importlib", "_freeze_importlib.vcxproj", "{19C0C13F-47CA-4432-AFF3-799A296A4DDC}"

+EndProject

 Global

 	GlobalSection(SolutionConfigurationPlatforms) = preSolution

 		Debug|Win32 = Debug|Win32

@@ -600,6 +602,20 @@
 		{1D4B18D3-7C12-4ECB-9179-8531FF876CE6}.Release|Win32.Build.0 = Release|Win32

 		{1D4B18D3-7C12-4ECB-9179-8531FF876CE6}.Release|x64.ActiveCfg = Release|Win32

 		{1D4B18D3-7C12-4ECB-9179-8531FF876CE6}.Release|x64.Build.0 = Release|Win32

+		{19C0C13F-47CA-4432-AFF3-799A296A4DDC}.Debug|Win32.ActiveCfg = Debug|Win32

+		{19C0C13F-47CA-4432-AFF3-799A296A4DDC}.Debug|Win32.Build.0 = Debug|Win32

+		{19C0C13F-47CA-4432-AFF3-799A296A4DDC}.Debug|x64.ActiveCfg = Debug|x64

+		{19C0C13F-47CA-4432-AFF3-799A296A4DDC}.Debug|x64.Build.0 = Debug|x64

+		{19C0C13F-47CA-4432-AFF3-799A296A4DDC}.PGInstrument|Win32.ActiveCfg = Release|Win32

+		{19C0C13F-47CA-4432-AFF3-799A296A4DDC}.PGInstrument|Win32.Build.0 = Release|Win32

+		{19C0C13F-47CA-4432-AFF3-799A296A4DDC}.PGInstrument|x64.ActiveCfg = Release|Win32

+		{19C0C13F-47CA-4432-AFF3-799A296A4DDC}.PGUpdate|Win32.ActiveCfg = Release|Win32

+		{19C0C13F-47CA-4432-AFF3-799A296A4DDC}.PGUpdate|Win32.Build.0 = Release|Win32

+		{19C0C13F-47CA-4432-AFF3-799A296A4DDC}.PGUpdate|x64.ActiveCfg = Release|Win32

+		{19C0C13F-47CA-4432-AFF3-799A296A4DDC}.Release|Win32.ActiveCfg = Release|Win32

+		{19C0C13F-47CA-4432-AFF3-799A296A4DDC}.Release|Win32.Build.0 = Release|Win32

+		{19C0C13F-47CA-4432-AFF3-799A296A4DDC}.Release|x64.ActiveCfg = Release|x64

+		{19C0C13F-47CA-4432-AFF3-799A296A4DDC}.Release|x64.Build.0 = Release|x64

 	EndGlobalSection

 	GlobalSection(SolutionProperties) = preSolution

 		HideSolutionNode = FALSE