Bring r17924 from trunk to 1.8 branch:
Add detection for POSIX lstat() routine to configure script (mostly for
non-UNIX/Linux machines) and add macro wrapper for it.
Alphabetatize the system/library calls we test for, to make them easier
to read.
Removed the sigaction() detection & macro wrappers, since it's not
used by the distribution currently.
Tested on:
FreeBSD/32 6.3 (duty) in debug mode
(h5committested on trunk)
