> hoping to push the changes to the project. I guess I am maintaining that myself now.
Not just the changes, you'd push the responsibility, too, for supporting a whole new compilation target. I don't know how big this is, but if it's a big enough hassle to keep maintaining this yourself, then consider that this maintenance work is really what you were hoping to push. So, depeding on which, you might be fine maintaining this, or the maintainers might have rejected the change, anyway.
Not just the changes, you'd push the responsibility, too, for supporting a whole new compilation target. I don't know how big this is, but if it's a big enough hassle to keep maintaining this yourself, then consider that this maintenance work is really what you were hoping to push. So, depeding on which, you might be fine maintaining this, or the maintainers might have rejected the change, anyway.