Restore lua 5.2/5.3 compatibility (fixes #1408)

src/common/runtime.cpp

@@ -879,4 +879,13 @@ Type *luax_type(lua_State *L, int idx)
 	return Type::byName(luaL_checkstring(L, idx));
 }
 
+int luax_resume(lua_State *L, int nargs)
+{
+#if LUA_VERSION_NUM >= 502
+	return lua_resume(L, nullptr, nargs);
+#else
+	return lua_resume(L, nargs);
+#endif
+}
+
 } // love

src/common/runtime.h

@@ -676,6 +676,11 @@ int luax_catchexcept(lua_State *L, const T& func, const F& finallyfunc)
 	return 0;
 }
 
+/**
+ * Compatibility shim for lua_resume
+ **/
+int luax_resume(lua_State *L, int nargs);
+
 } // love
 
 #endif // LOVE_RUNTIME_H