renderdoc: Check for `_WIN32` symbol rather than `WIN32`

src/core/tools/renderdoc.cpp

@@ -7,7 +7,7 @@
 #include "common/dynamic_library.h"
 #include "core/tools/renderdoc.h"
 
-#ifdef WIN32
+#ifdef _WIN32
 #include <windows.h>
 #else
 #include <dlfcn.h>