configure: enable the surfaceless platform by default

A simple platform that you want to use in a many usecases. See the
spec file details.

It has no special requirements plus it takes less than a second to
build.

Cc: mesa-stable@lists.freedesktop.org
Signed-off-by: Emil Velikov <emil.velikov@collabora.com>
Acked-by: Tapani Pälli <tapani.palli@intel.com>
Reviewed-by: Eric Engestrom <eric@engestrom.ch>
diff --git a/configure.ac b/configure.ac
index de42210..f741efc 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1643,10 +1643,9 @@
     [with_egl_platforms=auto])
 
 if test "x$with_egl_platforms" = xauto; then
+    with_egl_platforms="x11,surfaceless"
     if test "x$enable_gbm" = xyes; then
-        with_egl_platforms="x11,drm"
-    else
-        with_egl_platforms="x11"
+        with_egl_platforms="$with_egl_platforms,drm"
     fi
 else
     AC_MSG_WARN([--with-egl-platforms is deprecated. Use --with-platforms instead.])