glx: Add matching ifdef directives for driFetchDrawable declaration.
Fix macOS build error.
In file included from ../src/glx/glxext.c:53:
../src/glx/dri_common.h:58:8: error: unknown type name '__GLXDRIdrawable'; did you mean '__DRIdrawable'?
extern __GLXDRIdrawable *
^~~~~~~~~~~~~~~~
__DRIdrawable
../include/GL/internal/dri_interface.h:65:34: note: '__DRIdrawable' declared here
typedef struct __DRIdrawableRec __DRIdrawable;
^
Fixes: b699d070a6de ("glx: set the loader_logger early and for everyone")
Closes: https://gitlab.freedesktop.org/mesa/mesa/issues/2726
Signed-off-by: Vinson Lee <vlee@freedesktop.org>
cc: @evelikov