ui/egl: default to GLES on windows

Windows GL drivers are notoriously not very good. Otoh, ANGLE provides
rock solid GLES implementation on top of direct3d. We should recommend
it and default to ES when using EGL (users can easily override this if
necessary)

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20230606115658.677673-14-marcandre.lureau@redhat.com>

ui/egl-helpers.c

@@ -535,6 +535,10 @@ int qemu_egl_init_dpy_mesa(EGLNativeDisplayType dpy, DisplayGLMode mode)
 #ifdef WIN32
 int qemu_egl_init_dpy_win32(EGLNativeDisplayType dpy, DisplayGLMode mode)
 {
+    /* prefer GL ES, as that's what ANGLE supports */
+    if (mode == DISPLAYGL_MODE_ON) {
+        mode = DISPLAYGL_MODE_ES;
+    }
     return qemu_egl_init_dpy(dpy, 0, mode);
 }
 #endif