Fixed building on Windows with cmake, ninja, and clang

CMakeLists.txt

@@ -208,7 +208,7 @@ if(APPLE OR ARCH_64)
     set(OPT_DEF_SSEMATH ON)
   endif()
 endif()
-if(UNIX OR MINGW OR MSYS OR USE_CLANG OR VITA)
+if(UNIX OR MINGW OR MSYS OR (USE_CLANG AND NOT WINDOWS) OR VITA)
   set(OPT_DEF_LIBC ON)
 endif()