Forward CCFLAGS to Visual Studio project for IntelliSense.

SConscript

@@ -894,7 +894,10 @@ def _dump() -> None:
                 'args': target.args,
                 # 'kwargs': kwargs, <- circular dependency here and the json encoder doesn't like that
                 'CPPDEFINES': kwargs.get('CPPDEFINES', env['CPPDEFINES']),
-                'CPPPATH': kwargs.get('CPPPATH', env['CPPPATH'])
+                'CPPPATH': kwargs.get('CPPPATH', env['CPPPATH']),
+                'CFLAGS': kwargs.get('CFLAGS', env['CFLAGS']),
+                'CCFLAGS': kwargs.get('CCFLAGS', env['CCFLAGS']),
+                'CXXFLAGS': kwargs.get('CXXFLAGS', env['CXXFLAGS'])
             }
         return result