Re: problems building emacs with libgpm & gnutls on an old Debian system (Jessie)

[Robert Pluim <rpluim@gmail.com>]

>>>>> On Thu, 06 Aug 2020 17:05:16 +0100, Eric S Fraga <e.fraga@ucl.ac.uk> said:

    Eric> Hello,
    Eric> Without giving all the gory details, I am trying to build a recent emacs
    Eric> 28.x version (from git) on an old computer running Debian Jessie,
    Eric> i.e. Linux circa 2014-2015.

    Eric> I can configure and compile Emacs if I use --with-gnutls=ifavailable but
    Eric> not having libgnutls-dev or libgmp-dev installed.  This Emacs then runs
    Eric> but has problems with accessing email (gnus).  I can live with this to
    Eric> some degree as it meets one of my main requirements which is for writing
    Eric> prose.  But it would be nice to have email on it as well.

Nothing stops you from using  lisp/obsolete/{tls,starttls}.el , which
will wrap gnutls-cli or 'openssl s_client' for you, although itʼs not
a path I'drecommend.

    Eric> If I install the gnutls library, this brings in libgmp and then Emacs
    Eric> does not build.  I get error messages along the lines of:

    Eric> ,----
    Eric> | floatfns.o: In function `Fabs':
    Eric> | /home/ucecesf/git/emacs/src/floatfns.c:279: undefined reference to `mpz_sgn'
    Eric> | /home/ucecesf/git/emacs/src/floatfns.c:281: undefined reference to `mpz_neg'
    Eric> `----

    Eric> The strange thing is that mpz_sgn, for instance, is a #define in gpm.h
    Eric> but is not in gmpxx.h.  Both of these include files come from
    Eric> libgmp-dev.  It could be that Emacs's configure script picks up the
    Eric> wrong one?

    Eric> The versions of the two packages in question are:

    Eric> libgmp-dev:armhf        2:6.0.0+dfsg-6
    Eric> libgnutls28-dev:armhf   3.3.8-6+deb8u7   

    Eric> Am I doing something incredibly stupid (I have RTFMed but haven't seen
    Eric> anything that would help)?  Do I need to build those packages from
    Eric> source maybe?   

I think you can configure emacs using '--without-libgmp', then it will
use a builtin version of gmp. Iʼm assuming that linking to libgnutls
only has a runtime dependency on libgmp, not a requirement to have
access to gmp headers.

Maybe just uninstalling libgmp-dev but leaving libgmp installed is
enough?

Robert