cmake: don't use /NODEFAULTLIB if we are using the C runtime (thanks, Rob!).

Fixes Bugzilla #3640.

CMakeLists.txt

@@ -1584,7 +1584,7 @@ if(SDL_SHARED)
       SOVERSION ${LT_REVISION}
       OUTPUT_NAME "SDL2")
   endif()
-  if(MSVC)
+  if(MSVC AND NOT LIBC)
     # Don't try to link with the default set of libraries.
     set_target_properties(SDL2 PROPERTIES LINK_FLAGS_RELEASE "/NODEFAULTLIB")
     set_target_properties(SDL2 PROPERTIES LINK_FLAGS_DEBUG "/NODEFAULTLIB")
@@ -1599,7 +1599,7 @@ if(SDL_STATIC)
   add_library(SDL2-static STATIC ${SOURCE_FILES})
   set_target_properties(SDL2-static PROPERTIES OUTPUT_NAME "SDL2")
   set_target_properties(SDL2-static PROPERTIES POSITION_INDEPENDENT_CODE ${SDL_STATIC_PIC})
-  if(MSVC)
+  if(MSVC AND NOT LIBC)
     set_target_properties(SDL2-static PROPERTIES LINK_FLAGS_RELEASE "/NODEFAULTLIB")
     set_target_properties(SDL2-static PROPERTIES LINK_FLAGS_DEBUG "/NODEFAULTLIB")
     set_target_properties(SDL2-static PROPERTIES STATIC_LIBRARY_FLAGS "/NODEFAULTLIB")