On platforms where closefrom returns void (eg glibc>=2.34) the prototype
for closefrom in its compat tests would cause compile errors. Remove
this and have the tests pull in the compat headers in the same way as
the main code. bz#3336.
POSIX specifies that when given a symlink, AT_SYMLINK_NOFOLLOW should
update the symlink and not the destination. The compat code doesn't
have a way to do this, so where possible it fails instead of following a
symlink when explicitly asked not to. Instead of checking for an explicit
failure, check that it does not update the destination, which both the
real and compat implmentations should honour.
Inspired by github pull req #125 from chutzpah at gentoo.org.
Darren Tucker