CodeGit Merge Request #10: fix clang16 configure error (rejected)

clang16 throws an error because of the implicit function declaration of exit().
This leads to the wrong assumption that snprintf is not present on the system.

Bug: https://bugs.gentoo.org/906535
See also: https://wiki.gentoo.org/wiki/Modern_C_porting

[Alexander Perepelkin]

Hello @schievel1,

Thanks a lot for your efforts in submitting this merge request!
A similar fix for the same problem, implemented slightly differently, was committed a bit earlier here:
https://sourceforge.net/p/log4cpp/codegit/ci/6448ecddc8d7fdf2179bbce574cec7341181295c/
and was released with the library version log4cpp-1.1.4 on 2023-05-01