store a glibc->gnulib patch in the gnulib repository, and have a tool import the original file from glibc CVS, and apply the patch?
I believe it would be easy to change srclist-update to do this. For a given gnulib/file.c it could check for the existence of gnulib/file.c.patch and if present, apply it to the original source file before updating. We already perform license modifications on upstream files, so no new ground is being broken. So if you or others would like to do updates this way, that's fine, it can be supported. I (or anyone else) can hack srclist-update. srclist-update took about 15 minutes to write, it is nothing special. Best, karl