Require the XSync and XShape extensions at build-time

It's been long enough. We can mandate support for these, at least
at build-time. The code doesn't actually compile without either
of these, so just consider that unsupported.

src/core/main.c

@@ -125,16 +125,6 @@ log_handler (const gchar   *log_domain,
 static void
 meta_print_compilation_info (void)
 {
-#ifdef HAVE_SHAPE
-  meta_verbose ("Compiled with shape extension\n");
-#else
-  meta_verbose ("Compiled without shape extension\n");
-#endif
-#ifdef HAVE_XSYNC
-  meta_verbose ("Compiled with sync extension\n");
-#else
-  meta_verbose ("Compiled without sync extension\n");
-#endif
 #ifdef HAVE_RANDR
   meta_verbose ("Compiled with randr extension\n");
 #else