add inline testing using TEST_INLINING envvar

dtool/pptempl/Global.gmsvc.pp

@@ -61,6 +61,7 @@
 
 #defer CFLAGS_SHARED
 #defer OPTFLAGS /O2 /Ob1 /Ogity /G6
+//#defer OPTFLAGS /O2 /G6  (this is actually equivalent to above)
 
 #defer CDEFINES_OPT1 _DEBUG
 #defer CDEFINES_OPT2 _DEBUG
@@ -96,7 +97,13 @@
 #defer interrogate_ipath $[decygwin %,-I"%",$[target_ipath]]
 #defer interrogate_spath $[decygwin %,-S"%",$[install_parser_inc_dir]]
 
-#defer extra_cflags /W3 /EHsc /Zm250 /DWIN32_VC /DWIN32
+#if $[TEST_INLINING]
+#define WARNING_LEVEL_FLAG /W4 /DTEST_INLINING
+#else
+#define WARNING_LEVEL_FLAG /W3
+#endif
+
+#defer extra_cflags /EHsc /Zm250 /DWIN32_VC /DWIN32 $[WARNING_LEVEL_FLAG]
 
 #defer COMPILE_C cl /nologo /c /Fo"$[osfilename $[target]]" $[decygwin %,/I"%",$[ipath]] $[flags] $[extra_cflags] $[source]
 #defer COMPILE_C++ $[COMPILE_C]

dtool/pptempl/Global.msvc.pp

@@ -104,7 +104,13 @@
 #defer interrogate_ipath $[decygwin %,-I"%",$[target_ipath]]
 #defer interrogate_spath $[decygwin %,-S"%",$[install_parser_inc_dir]]
 
-#defer extra_cflags /W3 /EHsc /Zm250 /DWIN32_VC /DWIN32
+#if $[TEST_INLINING]
+#define WARNING_LEVEL_FLAG /W4 /DTEST_INLINING
+#else
+#define WARNING_LEVEL_FLAG /W3
+#endif
+
+#defer extra_cflags /EHsc /Zm250 /DWIN32_VC /DWIN32 $[WARNING_LEVEL_FLAG]
 
 #defer COMPILE_C cl /nologo /c /Fo"$[osfilename $[target]]" $[decygwin %,/I"%",$[ipath]] $[flags] $[extra_cflags] $[source]
 #defer COMPILE_C++ $[COMPILE_C]

dtool/src/dtoolbase/dtoolbase_cc.h

@@ -51,10 +51,15 @@ using namespace std;
 using namespace std;
 #endif
 
-#define INLINE inline
 #define TYPENAME typename
 
 #if defined(WIN32_VC) && !defined(LINK_ALL_STATIC)
+
+#ifdef TEST_INLINING
+#define INLINE __forceinline
+#else
+#define INLINE inline
+#endif
 // This macro must be used to export an instantiated template class
 // from a DLL.  If the template class name itself contains commas, it
 // may be necessary to first define a macro for the class name, to
@@ -63,6 +68,7 @@ using namespace std;
   exptp template class expcl classname;
 #else
 #define EXPORT_TEMPLATE_CLASS(expcl, exptp, classname)
+#define INLINE inline
 #endif
 
 // We define the macro PUBLISHED to mark C++ methods that are to be