Created attachment 286407 [details] Build log. Package dev-lang/mono doesn't builds without sys-devel/bison. The error is: configure: error: You need to install bison Please, add sys-devel/bison as a build time dependency of dev-lang/mono.
+ 16 Sep 2011; Pacho Ramos <pacho@gentoo.org> mono-2.10.5.ebuild: + Add virtual/yacc to DEPEND per bug #382911 by bay. +