Same error as in bug# 465644 (see there for buidl log). Bug got fixed already last year (see bug# 465828 comment# 10) in tkimg-1.4-r9 but that version is still not stabilized. tkimg-1.4-r9 builds without problems. Maybe time for an stable request?
+ 06 Mar 2014; Justin Lecher <jlec@gentoo.org> -tkimg-1.4-r7.ebuild, + -files/tkimg-1.4-jbig.patch, -files/tkimg-1.4-libtiff.patch, + -files/tkimg-1.4-libtiff4.patch, -files/tkimg-1.4-zlib-1.2.6.patch, + -files/tkimg-1.4-zlib127-gzgetc_fix.patch: + Drop old, #497702 +