Hard links in glibc build?

[Stan Shebs]

In the course of building current glibc using Google's internal
filesystems, we've run across a handful of places (nptl/Makefile etc) that
use ln -f instead of the configure setting LN_S, but the filesystem we use
for building does not allow hard links, and we've patched glibc locally to
make symlinks, which seems to work fine.  Is there some arcane reason that
these need to be hard links, or can everything be changed to use symlinks?