I was doing an "emerge -uvD world" and I would get an error stating "configure: error: XML:Parser perl module is required for intltool". This error first showed up on the ebuild for gtksourceview-0.7.1. I was able to figure out that portage was not including the dependency for dev-perl/XML-Parser. I was told to report a bug for this.
you should rebuild your perl engines when do a major perl update, the dep in gktsourceview is correct.
quick fix for you : rebuild XML-Parser
*** This bug has been marked as a duplicate of 41124 ***