as they say (http://gltt.sourceforge.net/download.html) "GLTT requires version FreeType version 1.3.1. GLTT does not work with FreeType2..." but ebuild's DEPENDS says >=media-libs/freetype-1.3.1 changing it on something like ~media-libs/freetype-1.3.1 or =media-libs/freetype-1.3.1* should help i guess.
good call, thanks for that.