Emscripten: Fixed compiler error.

include/bx/os.h

@@ -7,10 +7,10 @@
 #define BX_OS_H_HEADER_GUARD
 
 #include "bx.h"
+#include "debug.h"
 
 #if BX_PLATFORM_WINDOWS || BX_PLATFORM_WINRT
 #	include <windows.h>
-#   include "debug.h"
 #elif BX_PLATFORM_ANDROID \
 	|| BX_PLATFORM_EMSCRIPTEN \
 	|| BX_PLATFORM_FREEBSD \