[PATCH] gdb: use libtool in GDB_AC_CHECK_BFD

[Nick Alcock]

On 11 Nov 2022, Simon Marchi stated:

> Another idea I thought of, which would still break the API (in that
> callers would need to include a new source file) but not the ABI would
> be to put that declaration in a separate header, say ctf-gzip-api.h.
> Users of ctf-api.h would not have to deal with zlib.  Users of
> ctf-gzip-api.h would have to deal with zlib, but that's fine because
> they are consciously using it.

This thing is distinctly rarely used, so I'd say this is the best
suggestion so far: it unbreaks gdb and all known existing users can
definitely adapt easily, and it avoids depending on nasty guts of zlib.
If ctf-gzip-api.h #included ctf-api.h itself, the needed change to users
would be even smaller.

I'm trying to get a new libctf patch series into shape and can add this
change to it if you like: alternatively, consider a suitable patch
pre-approved. (You'll need to add a suitable #include to
libctf/ctf-serialize.c.)