Bug#1065107: exim4: FTBFS: missing build-dep on libnsl-dev

[Aurelien Jarno]

Source: exim4
Version: 4.97-1
Severity: serious
Tags: ftbfs
Justification: fails to build from source (but built successfully in the past)
User: debian-glibc at lists.debian.org
Usertags: libnsl-dev

Dear maintainer,

Starting with glibc 2.31, support for NIS (libnsl library) has been
moved to a separate libnsl2 package. In order to allow a smooth
transition, a libnsl-dev has been added to the libc6-dev package.

This dependency has been temporarily dropped in the 2.37-15.1 NMU, as
part of the 64-bit time_t transition. This causes exim4 to FTBFS in sid
with:

| cc buildconfig.c
| cc -g -O2 -ffile-prefix-map=/<<PKGBUILDDIR>>=. -fstack-protector-strong -fstack-clash-protection -Wformat -Werror=format-security -fcf-protection  -D_LARGEFILE_SOURCE -fno-strict-aliasing -Wall -Wdate-time -D_FORTIFY_SOURCE=2 -fvisibility=hidden  -o buildconfig buildconfig.c -lcrypt -lm -lnsl
| buildconfig.c: In function 'main':
| buildconfig.c:117:5: warning: unused variable 'test_int_t' [-Wunused-variable]
|   117 | int test_int_t = 0;
|       |     ^~~~~~~~~~
| /usr/bin/ld: cannot find -lnsl: No such file or directory
| collect2: error: ld returned 1 exit status
| make[3]: *** [Makefile:390: buildconfig] Error 1
| make[3]: Leaving directory '/<<PKGBUILDDIR>>/b-exim4-daemon-light/build-Linux-x86_64'
| make[2]: *** [Makefile:37: all] Error 2
| make[2]: Leaving directory '/<<PKGBUILDDIR>>/b-exim4-daemon-light'
| make[1]: *** [debian/rules:121: override_dh_auto_build] Error 2
| make[1]: Leaving directory '/<<PKGBUILDDIR>>'
| make: *** [debian/rules:324: build] Error 2
| dpkg-buildpackage: error: debian/rules build subprocess returned exit status 2

This could be fixed by adding an explicit Build-Depends on libnsl-dev.
The glibc change will likely be reverted in the short term, but given
its a change we want to do for Trixie, this will only lower the severity
of the bug.

Regards
Aurelien