bpo-36097: Use only public C-API in the_xxsubinterpreters module (adding as necessary). (gh-12359)

diff --git a/PCbuild/pythoncore.vcxproj b/PCbuild/pythoncore.vcxproj
index bff7b95..c9ff2f8 100644
--- a/PCbuild/pythoncore.vcxproj
+++ b/PCbuild/pythoncore.vcxproj
@@ -154,6 +154,7 @@
     <ClInclude Include="..\Include\internal\pycore_pystate.h" />
     <ClInclude Include="..\Include\internal\pycore_tupleobject.h" />
     <ClInclude Include="..\Include\internal\pycore_warnings.h" />
+    <ClInclude Include="..\Include\interpreteridobject.h" />
     <ClInclude Include="..\Include\intrcheck.h" />
     <ClInclude Include="..\Include\iterobject.h" />
     <ClInclude Include="..\Include\listobject.h" />
@@ -350,6 +351,7 @@
     <ClCompile Include="..\Objects\frameobject.c" />
     <ClCompile Include="..\Objects\funcobject.c" />
     <ClCompile Include="..\Objects\genobject.c" />
+    <ClCompile Include="..\Objects\interpreteridobject.c" />
     <ClCompile Include="..\Objects\iterobject.c" />
     <ClCompile Include="..\Objects\listobject.c" />
     <ClCompile Include="..\Objects\longobject.c" />
diff --git a/PCbuild/pythoncore.vcxproj.filters b/PCbuild/pythoncore.vcxproj.filters
index 0303074..5dfa193 100644
--- a/PCbuild/pythoncore.vcxproj.filters
+++ b/PCbuild/pythoncore.vcxproj.filters
@@ -483,6 +483,9 @@
     <ClInclude Include="..\Include\namespaceobject.h">
       <Filter>Include</Filter>
     </ClInclude>
+    <ClInclude Include="..\Include\interpreteridobject.h">
+      <Filter>Include</Filter>
+    </ClInclude>
     <ClInclude Include="..\Modules\hashtable.h">
       <Filter>Modules</Filter>
     </ClInclude>
@@ -1043,6 +1046,9 @@
     <ClCompile Include="..\Objects\namespaceobject.c">
       <Filter>Objects</Filter>
     </ClCompile>
+    <ClCompile Include="..\Objects\interpreteridobject.c">
+      <Filter>Objects</Filter>
+    </ClCompile>
     <ClCompile Include="..\Modules\_opcode.c">
       <Filter>Modules</Filter>
     </ClCompile>