GIMP 1.2.3-r2 doesn't generate locales. It seems that the problem is related to automake/autoconf. When using the tar.bz2 directly, there's no problem. But when regenerating the Makefiles using automake/autoconf, the configure script skips the locales.
Created attachment 4269 [details, diff] Patch to replace the one provided with the portage tree This patch is based on Makefile.in, avoiding the use of autoconf/automake
Created attachment 4270 [details, diff] Lines to remove from the ebuild
Try media-gfx/gimp-1.2.3-r3.
Yeah, -r3 works. thanks. bug can be closed in my opinion.