Avoid link tests in NPTL configure

[Roland McGrath]

That seems OK, though I would prefer that the test not explicitly declare
and then use a standard function.  I'm not really sure why that test needs
to have a function call after the declaration at all.  But if it does, then
using a call to a locally-defined function or an external, undefined
function with a nonstandard name seems better.


Thanks,
Roland