I've reverted the master branch up to commit 15f90529ee13 (2024-07-27) in an attempt to restore a stable working point. Recent attempts at fixing the build system (e.g. to run after "make maintainer-clean" was run) have only made things worse. "make distcheck" was not working due to an attempt to rebuild pod2texi.texi in a read-only srcdir.
I have tested this by running ./autogen.sh ./configure make make distcheck I hope that any further changes should at least pass this basic check. (Unfortunately it takes a few minutes to run due to the test suite running.)