bpo-35081: Add new internal headers to Makefile (GH-10670)

Add pycore_fileutils.h and pycore_object.h to Makefile.pre.in and to
the pythoncore project of PCbuild/.
diff --git a/Makefile.pre.in b/Makefile.pre.in
index 87a84eb..2b5afae 100644
--- a/Makefile.pre.in
+++ b/Makefile.pre.in
@@ -1029,9 +1029,11 @@
 		$(srcdir)/Include/internal/pycore_ceval.h \
 		$(srcdir)/Include/internal/pycore_condvar.h \
 		$(srcdir)/Include/internal/pycore_context.h \
+		$(srcdir)/Include/internal/pycore_fileutils.h \
 		$(srcdir)/Include/internal/pycore_getopt.h \
 		$(srcdir)/Include/internal/pycore_gil.h \
 		$(srcdir)/Include/internal/pycore_hamt.h \
+		$(srcdir)/Include/internal/pycore_object.h \
 		$(srcdir)/Include/internal/pycore_pathconfig.h \
 		$(srcdir)/Include/internal/pycore_pyhash.h \
 		$(srcdir)/Include/internal/pycore_pylifecycle.h \
diff --git a/PCbuild/pythoncore.vcxproj b/PCbuild/pythoncore.vcxproj
index 0ae24fa..885d602 100644
--- a/PCbuild/pythoncore.vcxproj
+++ b/PCbuild/pythoncore.vcxproj
@@ -116,9 +116,11 @@
     <ClInclude Include="..\Include\internal\pycore_ceval.h" />
     <ClInclude Include="..\Include\internal\pycore_condvar.h" />
     <ClInclude Include="..\Include\internal\pycore_context.h" />
+    <ClInclude Include="..\Include\internal\pycore_fileutils.h" />
     <ClInclude Include="..\Include\internal\pycore_getopt.h" />
     <ClInclude Include="..\Include\internal\pycore_gil.h" />
     <ClInclude Include="..\Include\internal\pycore_hamt.h" />
+    <ClInclude Include="..\Include\internal\pycore_object.h" />
     <ClInclude Include="..\Include\internal\pycore_pathconfig.h" />
     <ClInclude Include="..\Include\internal\pycore_pyhash.h" />
     <ClInclude Include="..\Include\internal\pycore_pylifecycle.h" />
diff --git a/PCbuild/pythoncore.vcxproj.filters b/PCbuild/pythoncore.vcxproj.filters
index ef5ef72..2af11c9 100644
--- a/PCbuild/pythoncore.vcxproj.filters
+++ b/PCbuild/pythoncore.vcxproj.filters
@@ -147,6 +147,9 @@
     <ClInclude Include="..\Include\internal\pycore_context.h">
       <Filter>Include</Filter>
     </ClInclude>
+    <ClInclude Include="..\Include\internal\pycore_fileutils.h">
+      <Filter>Include</Filter>
+    </ClInclude>
     <ClInclude Include="..\Include\internal\pycore_getopt.h">
       <Filter>Include</Filter>
     </ClInclude>
@@ -156,6 +159,9 @@
     <ClInclude Include="..\Include\internal\pycore_hamt.h">
       <Filter>Include</Filter>
     </ClInclude>
+    <ClInclude Include="..\Include\internal\pycore_object.h">
+      <Filter>Include</Filter>
+    </ClInclude>
     <ClInclude Include="..\Include\internal\pycore_pathconfig.h">
       <Filter>Include</Filter>
     </ClInclude>