>> if test "`(eval $ac_link 2>&1 1>&5)`" = "" && test "`(eval>> $ac_compile 2>&1 1>&5)`" = ""; then
FWIW, I happened to run into this recently on IRC with someone having
compile problems on FreeBSD (10.1); they were using some nonstandard
compile flags, and configure's pthread test was breaking as a result
(they did not report what the actual warning was).
While investigating that, I also noticed that this code prevents any
attempt at running configure with -x in effect from working properly,
making it a bit hard to debug.
--
Andrew (irc:RhodiumToad)