soname bump and libraries used during testing

[Eray Aslan]

Hi,

A user reported test failure in mailutils-3.14:

/var/tmp/portage/net-mail/mailutils-3.14-r1/work/mailutils-3.14/mda/putmail/.libs/putmail:
symbol lookup error:
/var/tmp/portage/net-mail/mailutils-3.14-r1/work/mailutils-3.14/mda/putmail/.libs/putmail:
undefined symbol: mu_locker_defaults

I can reproduce the error on a system with mailutils-3.12 installed.

1/
some dropped symbols were reported for mailutils-3.14:
https://lists.gnu.org/archive/html/bug-mailutils/2022-03/msg00000.html

similarly, there were changes in libmailutils in 3.13 without a soname
bump.  Sergey already replied that he will bump the soname for next
release so we should be ok there.

2/
In addition, during testing, an already installed mailutils library
takes precedence over the newly built one. Hence, we get the undefined
symbol error because that symbol is defined in libmailutils-3.14 but not
on mailutils-3.12.  I believe our tests should run using newly built
libraries and not against an already installed potentially old and
uncompatible library.

We were testing on a system without mailutils installed and therefore
missed this failure. Any version test in the testsuite should fail if
there is a different version of mailutils already installed in the
system.

Nothing urgent. Just something to keep in mind for the next release(s).

Thank you,
-- 
Eray