Darnit, that last commit was only supposed to change files in the
-current branch. I mistakenly checked out the 2.2.x rpc.ypxfrd into my
-current working directory. No harm done, but I got really confused
when I went to check out rpc.ypxfrd again and found the changes I
wanted to make were already there. (I'm going to fix the other 2.2.x
versions of the other programs in a minute.)

Anyway: protect errno in the signal handler, in the -current version
of rpc.ypxfrd this time.