Comment 22 for bug 144431

Both the Glibc upstream (http://sourceware.org/bugzilla/show_bug.cgi?id=4671) and Debian (http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=575209) seem to not want to fix this.

The patch in the Debian bugreport will allow hyphens; my patch is a little bit more liberal and allows underscores as well (it also cleans up the logic to make res_hnok more like res_dnok).

Tested on my system, and it seems to be working.