x11-apps/xmessage hasn't been needed since upstream WINE commit http://source.winehq.org/git/wine.git/commit/d270a9603261d7d3693b375e3e6f7809501d821a in April 2008. By removing it, it'll allow many users to not have x11-libs/libXaw on their systems either.
Fixed, thanks for reporting! > 12 Aug 2012; Alexandre Rostovtsev <tetromino@gentoo.org> wine-1.2.ebuild, > wine-1.2.1.ebuild, wine-1.2.2.ebuild, wine-1.2.3.ebuild, wine-1.3.0.ebuild, > wine-1.3.1.ebuild, wine-1.3.2.ebuild, wine-1.3.3.ebuild, wine-1.3.4.ebuild, > wine-1.3.5.ebuild, wine-1.3.6.ebuild, wine-1.3.7.ebuild, wine-1.3.8.ebuild, > wine-1.3.9.ebuild, wine-1.3.10.ebuild, wine-1.3.11.ebuild, > wine-1.3.12.ebuild, wine-1.3.13.ebuild, wine-1.3.14.ebuild, > wine-1.3.15.ebuild, wine-1.3.16.ebuild, wine-1.3.17.ebuild, > wine-1.3.18.ebuild, wine-1.3.19.ebuild, wine-1.3.20.ebuild, > wine-1.3.21.ebuild, wine-1.3.22.ebuild, wine-1.3.23.ebuild, > wine-1.3.24.ebuild, wine-1.3.25.ebuild, wine-1.3.26.ebuild, > wine-1.3.27.ebuild, wine-1.3.28.ebuild, wine-1.3.29.ebuild, > wine-1.3.30.ebuild, wine-1.3.31.ebuild, wine-1.3.32.ebuild, > wine-1.3.33.ebuild, wine-1.3.34.ebuild, wine-1.3.35.ebuild, > wine-1.3.36.ebuild, wine-1.3.37.ebuild, wine-1.4.ebuild, wine-1.4.1.ebuild, > wine-1.5.0.ebuild, wine-1.5.1.ebuild, wine-1.5.2.ebuild, wine-1.5.3.ebuild, > wine-1.5.4.ebuild, wine-1.5.5.ebuild, wine-1.5.6.ebuild, wine-1.5.7.ebuild, > wine-1.5.8.ebuild, wine-1.5.9.ebuild, wine-1.5.10.ebuild, wine-9999.ebuild: > xmessage not needed for >=wine-0.9.60 (bug #431140, thanks to Matt Turner).
