use win_amd64 instead of win64, and win_i386 instead of win32

dtool/src/dtoolbase/dtool_platform.h

@@ -26,10 +26,10 @@
 // This has already been defined explicitly by the Config.pp file.
 
 #elif defined(_WIN64)
-#define DTOOL_PLATFORM "win64"
+#define DTOOL_PLATFORM "win_amd64"
 
 #elif defined(_WIN32)
-#define DTOOL_PLATFORM "win32"
+#define DTOOL_PLATFORM "win_i386"
 
 #elif defined(__APPLE__)
 #if defined(BUILD_IPHONE)

dtool/src/dtoolutil/pandaSystem.cxx

@@ -297,8 +297,8 @@ get_build_date() {
 //       Access: Published, Static
 //  Description: Returns a string representing the runtime platform
 //               that we are currently running on.  This will be
-//               something like "win32" or "osx.i386" or
-//               "linux.amd64".
+//               something like "win32" or "osx_i386" or
+//               "linux_amd64".
 ////////////////////////////////////////////////////////////////////
 string PandaSystem::
 get_platform() {