egl-helpers: Support newer MESA versions

According to
https://www.khronos.org/registry/EGL/extensions/MESA/EGL_MESA_platform_gbm.txt


if MESA_platform_gbm is supported display should be initialized
from a GBM handle using eglGetPlatformDisplayEXT.

Signed-off-by: Frediano Ziglio <fziglio@redhat.com>
Message-id: 20170220095055.4234-1-fziglio@redhat.com
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

ui/egl-helpers.c

@@ -223,7 +223,11 @@ int qemu_egl_init_dpy(EGLNativeDisplayType dpy, bool gles, bool debug)
     }
 
     egl_dbg("eglGetDisplay (dpy %p) ...\n", dpy);
+#ifdef EGL_MESA_platform_gbm
+    qemu_egl_display = eglGetPlatformDisplayEXT(EGL_PLATFORM_GBM_MESA, dpy, NULL);
+#else
     qemu_egl_display = eglGetDisplay(dpy);
+#endif
     if (qemu_egl_display == EGL_NO_DISPLAY) {
         error_report("egl: eglGetDisplay failed");
         return -1;