There is a new version of jhead, although the changelog is confused about version number. The ebuild does not respect CFLAGS and LDFLAGS. Also, there is a warning about using mktemp(3) instead of mkstemp(3). I'm attaching two patches and a patch to the ebuild. Reproducible: Always I am not a security person, but I don't think the mstemp thing is an exploitable security vulnerability, that's why I'm not reporting this as a security bug.
Created attachment 195561 [details, diff] patch from ebuild in portage to new ebuild
Created attachment 195562 [details, diff] patch to makefile to respect flags
Created attachment 195564 [details, diff] patch to change use of mktemp to mkstemp
Thanks Zeev, now in cvs. Please, be sure to send the mkstemp patch to upstream. Cheers, Marcelo