According to Coverity, 194 ouf of 227 times we check for snprintf return code.
Voidify the rest.
CID#1461512
CID#1461513
CID#1461514
CID#1461515
CID#1461516
CID#1461518
CID#1461519
CID#1461520
CID#1461522
Inspired by https://bugzilla.redhat.com/show_bug.cgi?id=1929936.
This is similar to test-nss-hosts, but does users, groups, uid, gids.
Functions tested are:
_nss_*_getpwnam_r
_nss_*_getgrnam_r
_nss_*_getpwgid_r
_nss_*_getgrgid_r
Other entry points should be tested too, but it's not relevant to the bug
I was investigating, so I'm leaving that for later ;)