Gentoo's Bugzilla –
Attachment 364858 Details for
Bug 493580=x11-libs/libXft-2.3.1-r1 with =media-libs/freetype-2.5.1 - /var/tmp/portage/x11-libs/libXft-2.3.1-r1/work/libXft-2.3.1/src/xftglyphs.c:24:30: fatal error: freetype/ftoutln.h: No such file or directory