https://bugs.gentoo.org/844115#c21

Two of these files are provided by Adobe Type Tools:
https://github.com/adobe-type-tools/cmap-resources/tree/master/Adobe-Identity-0/CMap

and the third is from Artifex themselves:
http://git.ghostscript.com/?p=ghostpdl.git;a=blob;f=Resource/CMap/Identity-UTF16-H;hb=HEAD

(As noted in Ghostscript's LICENSE file, Identity-UTF16-H is licensed under AGPL-3+.)
