Created attachment 280715 [details]
You're receiving this canned (template-based) bug report because I found a problem with a package during my tinderbox run.
The package in question is running automake (and most likely other autotools) during compile phase by maintainer-mode. You can see in my blog post in the URL field why that's a problem, and how to address the issue, but in general, you don't want maintainer-mode rebuild during compile phase, especially since it can cause multiple run of econf.
The causes of maintainer-mode rebuild are various, but most likely it's because of a patch that changes Makefile.am or configure.ac/in and don't rebuild autotools properly. The way to fix this is almost always to inherit autotools eclass and run eautomake/eautoreconf (as needed; eautoconf should only be used when automake is not involved, which is not the case here) during src_unpack phase.
I cannot reproduce this
Maybe this could be caused by this:
# Remove themes now provided by x11-themes/gnome-themes-standard
sed 's:HighContrast.*\\:\\:g' -i $(find . -name Makefile.am -o -name Makefile.in) || die
sed 's:LowContrast.*\\:\\:g' -i $(find . -name Makefile.am -o -name Makefile.in) || die
And running separate sed commands for .am files and, later, for .in files could help. Please try it (as it still doesn't fail for me)