Avoid errors with stuff not build on --without-x

Reported by by Abhimanyu Singh

Change-Id: I02bd2a2b85b9d55f0b237d3a1141801245473cd2
Reviewed-on: https://gerrit.libreoffice.org/16453
Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Michael Stahl <mstahl@redhat.com>

scp2/source/ooo/file_ooo.scp

@@ -59,7 +59,7 @@ End
 
 #endif
 
-#if defined UNX && ! defined MACOSX
+#if defined UNX && ! defined MACOSX && ! defined LIBO_HEADLESS
 
 File gid_File_Bin_Gnome_Open_Url
     BIN_FILE_BODY;