Initialize context creation APIs on demand

src/cocoa_window.m

@@ -1034,6 +1034,8 @@ int _glfwPlatformCreateWindow(_GLFWwindow* window,
     {
         if (ctxconfig->source == GLFW_NATIVE_CONTEXT_API)
         {
+            if (!_glfwInitNSGL())
+                return GLFW_FALSE;
             if (!_glfwCreateContextNSGL(window, ctxconfig, fbconfig))
                 return GLFW_FALSE;
         }