In the glibc spec file make the following change. I'm not certain where you are picking up nsswitch.conf from, but I do not have a redhat directory in my glibc tree... s|redhat/nsswitch.conf|nss/nsswitch.conf| This is in the current Rawhide and RC1 source. The offending line is: install -m 644 redhat/nsswitch.conf $RPM_BUILD_ROOT/etc/nsswitch.conf
If you're building your own glibc, you'll have to modify glibc.spec not only because of this but for a couple of different things as well. The tarball we're shipping in glibc source rpm is a snapshot from our internal glibc CVS, which is basically a sourceware snapshot + diff-CYGNUS-to-REDHAT.patch applied plus a few new directories (like c-stubs, glibc-compat and redhat).