project: Rename build options

Following the new meson porting guidelines, this patch renames the
build options. The list of changes is as follows:

- Remove the enable prefix from boolean options.
- The character separator from multi-word options has been changed
  to underscore.

https://bugzilla.gnome.org/show_bug.cgi?id=790234

configure

@@ -159,7 +159,7 @@ END
 
 cmd_options=""
 for key in "${!meson_options[@]}"; do
-    cmd_options="$cmd_options -Denable-$key=${meson_options[$key]}"
+    cmd_options="$cmd_options -D${key/\-/_}=${meson_options[$key]}"
 done
 
 exec ${MESON} \