There is a bug in the sed call in the ebuild, it does not modify the correct Makefile and so Ghostscript is built with the wrong font search path: /usr/share/ghostscript/fonts instead of /usr/share/fonts/default/ghostscript. So documents without embedded fonts fail processing. It should be noted that initially Makefile.in is symlinked to src/Makefile.in. However, the behaviour of sed if --follow-symlinks is not specified is to break the link when -i is also used. Attached patch resolves this issue. This probably affects ghostscript-gpl too but I have not confirmed this.
Created attachment 121270 [details, diff] Patch
thank you, fixed