Update default name from OS X to macOS

Note that earlier releases are still referred to by their proper names;
OS X <version> or Mac OS X <version>.

src/win32_window.c

@@ -668,7 +668,7 @@ static LRESULT CALLBACK windowProc(HWND hWnd, UINT uMsg,
         case WM_MOUSEHWHEEL:
         {
             // This message is only sent on Windows Vista and later
-            // NOTE: The X-axis is inverted for consistency with OS X and X11.
+            // NOTE: The X-axis is inverted for consistency with macOS and X11
             _glfwInputScroll(window, -((SHORT) HIWORD(wParam) / (double) WHEEL_DELTA), 0.0);
             return 0;
         }