[3.14] GH-141808: Do not generate the jit stencils twice in case of PGO builds on Windows. (GH-142043) (#142100)

GH-141808: Do not generate the jit stencils twice in case of PGO builds on Windows. (GH-142043)

* do not build the jit stencils twice in case of PGO builds on Windows

* blurb it
(cherry picked from commit f2ca158)

Co-authored-by: Chris Eibl <138194463+chris-eibl@users.noreply.github.com>

Author: miss-islington

Misc/NEWS.d/next/Build/2025-11-28-19-49-01.gh-issue-141808.cV5K12.rst

@@ -0,0 +1 @@
+Do not generate the jit stencils twice in case of PGO builds on Windows.

PCbuild/pyproject.props

@@ -13,6 +13,7 @@
     <GeneratedFrozenModulesDir>$(Py_IntDir)\$(MajorVersionNumber)$(MinorVersionNumber)_frozen\</GeneratedFrozenModulesDir>
     <GeneratedZlibNgDir>$(Py_IntDir)\$(MajorVersionNumber)$(MinorVersionNumber)$(ArchName)_$(Configuration)\zlib-ng\</GeneratedZlibNgDir>
     <GeneratedJitStencilsDir>$(Py_IntDir)\$(MajorVersionNumber)$(MinorVersionNumber)_$(Configuration)</GeneratedJitStencilsDir>
+    <GeneratedJitStencilsDir Condition="$(Configuration) == 'PGUpdate'">$(Py_IntDir)\$(MajorVersionNumber)$(MinorVersionNumber)_PGInstrument</GeneratedJitStencilsDir>
     <TargetName Condition="'$(TargetName)' == ''">$(ProjectName)</TargetName>
     <TargetName>$(TargetName)$(PyDebugExt)</TargetName>
     <GenerateManifest>false</GenerateManifest>