Apparently waf fails to probe for the _libpopt-dev_ package during the configuration step, so the build fails:
> [3573/4441] Compiling source4/torture/krb5/kdc-canon-heimdal.c
> In file included from ../../source4/torture/krb5/kdc-canon-heimdal.c:28:0:
> ../../lib/cmdline/cmdline.h:22:10: fatal error: popt.h: Datei oder Verzeichnis nicht gefunden
> #include <popt.h>
> compilation terminated.
> Waf: Leaving directory `/home/mdw/progs/c_cpp/samba/bin/default'
> Build failed
> -> task in 'TORTURE_KRB5' failed with exit status 1 (run with -v to display more information)
> Makefile:7: recipe for target 'all' failed
> make: *** [all] Error 1
Installing it with the system's package manager resolves the problem :).