Can you please have a look if virtual/awk is sufficient or if gawk is needed.
configure allows mawk nawk gawk for awk (in that order), so virtual/awk should be fine.
+ 10 Mar 2013; Christoph Junghans <ottxor@gentoo.org> + hylafaxplus-5.5.1-r1.ebuild, hylafaxplus-5.5.1.ebuild: + switch to virtual/awk (bug #455674)