Can you please have a look if virtual/awk is sufficient or if gawk is needed.
nmbscan call awk, but only in posix-conform ways, so virtual/awk is fine.
+ 04 Mar 2013; Christoph Junghans <ottxor@gentoo.org> nmbscan-1.2.4.ebuild, + nmbscan-1.2.5.ebuild: + switched to virtual/awk (bug #455662)