See attached build log.
(Please do not complain about the need for looking at the build log until you can provide an easy way to open bugs with the correct data picked out of a tinderbox log. Thanks.)
Created attachment 242013 [details]
+ 09 Aug 2010; Kacper Kowalik <firstname.lastname@example.org> prank-100701.ebuild:
+ Respect user FLAGS wrt bug 331799. Thanks to Diego for report. Drop perl
+ from src_prepare.