atomic ops in heimdal: -latomic

[Michael Tokarev]

Hi!

Something changed - probably in Debian (where I build packages), and some stuff
started failing, eg

https://buildd.debian.org/status/fetch.php?pkg=samba&arch=armel&ver=2%3A4.18.3%2Bdfsg-1&stamp=1686556171&raw=0

/usr/bin/ld: third_party/heimdal/lib/krb5/krcache.c.55.o: in function `krcc_get_principal':
./bin/default/../../third_party/heimdal/lib/krb5/krcache.c:1395: undefined reference to `__atomic_load_8'
/usr/bin/ld: ./bin/default/../../third_party/heimdal/lib/krb5/krcache.c:1395: undefined reference to `__atomic_store_8'
/usr/bin/ld: third_party/heimdal/lib/krb5/krcache.c.55.o: in function `krcc_remove_cred':
./bin/default/../../third_party/heimdal/lib/krb5/krcache.c:1447: undefined reference to `__atomic_load_8'
/usr/bin/ld: ./bin/default/../../third_party/heimdal/lib/krb5/krcache.c:1447: undefined reference to `__atomic_store_8'
/usr/bin/ld: third_party/heimdal/lib/krb5/krcache.c.55.o: in function `initialize_internal':
./bin/default/../../third_party/heimdal/lib/krb5/krcache.c:873: undefined reference to `__atomic_load_8'
/usr/bin/ld: ./bin/default/../../third_party/heimdal/lib/krb5/krcache.c:873: undefined reference to `__atomic_store_8'
/usr/bin/ld: ./bin/default/../../third_party/heimdal/lib/krb5/krcache.c:919: undefined reference to `__atomic_load_8'
/usr/bin/ld: ./bin/default/../../third_party/heimdal/lib/krb5/krcache.c:919: undefined reference to `__atomic_store_8'
collect2: error: ld returned 1 exit status

Apparently this now needs -latomic on the link line. I don't know yet why it ended up like this,
but other projects which faced this same issue, just added -latomic in similar cases.

FWIW.

Thanks,

/mjt