configure: Re-run make if gtkabi/sdlabi is changed

Reconfiguring with a different --with-gtkabi or --with-sdlabi doesn't
trigger a remake. Generate an (unused) CONFIG_GTKABI/CONFIG_SDLABI
so config-host.h will actually give 'make' something to trigger on.

Signed-off-by: Cole Robinson <crobinso@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

configure

@@ -4350,6 +4350,7 @@ if test "$modules" = "yes"; then
 fi
 if test "$sdl" = "yes" ; then
   echo "CONFIG_SDL=y" >> $config_host_mak
+  echo "CONFIG_SDLABI=$sdlabi" >> $config_host_mak
   echo "SDL_CFLAGS=$sdl_cflags" >> $config_host_mak
 fi
 if test "$cocoa" = "yes" ; then
@@ -4433,6 +4434,7 @@ fi
 echo "GLIB_CFLAGS=$glib_cflags" >> $config_host_mak
 if test "$gtk" = "yes" ; then
   echo "CONFIG_GTK=y" >> $config_host_mak
+  echo "CONFIG_GTKABI=$gtkabi" >> $config_host_mak
   echo "GTK_CFLAGS=$gtk_cflags" >> $config_host_mak
 fi
 if test "$vte" = "yes" ; then