Sendfile should be changed to use gpg instead of pgp. As pgp is not in gentoo's portage system, all the SAFT signing & authentication functions are out of order as the pgp binary is not found.
Probably this is an upstream problem.
But please don't, in any case, remove the ebuild.
But there's obviously no real upstream.
There's a Debian version of sendfile available, probably it contains more patches to sendfile. (At least -26 does one more - dated 23 Nov 2001)
Until pgp makes it into the tree I don't see any way this could be done without rewriting sendfile.