Can you please have a look if virtual/awk is sufficient or if gawk is needed.
The only place outside of the build system, where awk is used for is gnome-doc-make.awk, which is executed with GDU_AWK="gawk --traditional", so virtual/awk is fine.
Fixed. + 12 Feb 2013; Alexandre Rostovtsev <tetromino@gentoo.org> + gnome-doc-utils-0.20.6.ebuild, gnome-doc-utils-0.20.9.ebuild, + gnome-doc-utils-0.20.10.ebuild: + Depend on virtual/awk instead of gawk, bug #455714, thanks to Christoph + Junghans.