Error in building libnss_compat

[Bob McCracken]

In glibc-2.2.3 the enum "__niserr2nss_tab" and the int "__niserr2nss_count"
are defined in nis/nss-nis.c. But the object file nss-nis.so is not linked in
when libnss_compat is built, and therefore "make check" gets indefined
references when testing libnss_compat.

In my previous glibc, 2.2.1, __niserr2nss_tab was defined in nis/nss-nis.h,
which caused no problem, and __niserr2nss_count seems not to occur at all in
that version.

        Bob McCracken