Added required define on TCC compiler

src/rglfw.c

@@ -45,6 +45,9 @@
     #define _GLFW_USE_MENUBAR       // To create and populate the menu bar when the first window is created
     #define _GLFW_USE_RETINA        // To have windows use the full resolution of Retina displays
 #endif
+#if defined(__TINYC__)
+    #define _WIN32_WINNT_WINXP		0x0501
+#endif
 
 // NOTE: _GLFW_MIR experimental platform not supported at this moment