With commit c25b3d2447 media-tv/xbmc-9999 fails to configure without dev-lang/swig. Checking for SWIG installation checking for swig... none configure: error: Could not find a required program. Please see the README for your platform.
Confirmed here, i had the same issue.
should be all set now in the tree; thanks for the report! Commit message: Add swig to DEPEND since upstream requires it http://sources.gentoo.org/media-tv/xbmc/xbmc-9999.ebuild?r1=1.121&r2=1.122