gtkspell requires the XML::Parser perl module to configure, but it is not included in the ebuilds dependencies. Here are a few lines of the build log for confirmation:
checking for perl... /usr/bin/perl
checking for perl >= 5.8.1... 5.12.1
checking for XML::Parser... configure: error: XML::Parser perl module is required for intltool
After installing XML-Parser, gtkspell builds as expected.
You may need to run perl-cleaner first.
*** This bug has been marked as a duplicate of bug 41124 ***
Why not add "perl-cleaner --reallyall" or similar to perl's ebuild pkg_postins and make this automatic every time perl is updated or downgraded? I have not programmed in perl in a decade, and have no idea of the nuances of maintaining a working perl installation on my cluster nor home machines.
Also, the last time I updated perl the cleaner_msg was buried in the middle of output from 265 packages that were updated in the middle of the night, and I never saw the message.