Hi Bruno, I have been bitten by portability issues with libtextstyle: some people have versions that don't feature ostream_printf. Unfortunately gnulib's Autoconf macros don't check for this function, so old versions of libtextstyle are accepted, and linking fails (https://lists.gnu.org/r/bug-bison/2020-07/msg00030.html). I have no idea where the prototype was found by the way.
I don't know how you want to handle this situation: 1. gnulib macros should be able to be told what requirements one has one libtextstyle 2. gnulib macros always aim at the most recent "release" but checking for the most recent additions in the API. I'd go for 2, but maybe you have a different opinion. Another point is that I expected --without-libtextstyle-prefix to disable explicitly libtextstyle, but apparently it doesn't (https://lists.gnu.org/r/bug-bison/2020-07/msg00037.html). I can submit changes once I know what options you prefer. Cheers!
