mount point. if /link is a link to a directory on a different file system, lstat(/link) and lstat(/link/file) have different .st_devs, even though /link/file is an ordinary file in a symlinked directory; stat(/link) and lstat(/link/file) have the same .st_devs, so I believe we should be testing that condition instead.
That's what the other mount helpers appear to be doing.
We need automake 1.11 in order to grok the 'serial-test' option. http://stackoverflow.com/questions/15820844/how-to-define-automake-options-conditionally
The underlying test file may change the order that attributes are returned so avoid depending on that.
Add missing quote around AC_LANG_PROGRAM invocation. https://lists.gnu.org/archive/html/bug-autoconf/2011-04/msg00015.html [from Mark Grondona in flux-core project]