I think the 2 subprojects actually need to be subdirs
This subprojects do not have
*.wrap file or additional git repos, thus it is impossible to be promoted. Since the code is maintained inside this repo directly. Thus the libnsgif and poly2tri-c do not match the subproject concept in meson. If you do it like this, the gegl can never be used as subproject in other projects unless creating symlink in top project.