AC_TRY_RUN() smashes $?

[Bill Fenner]

Hi,

  autoconf.texi says that the third argument of AC_TRY_RUN (action-if-false)
can use $?.  This is untrue; $? gets smashed by echo and cat.  autoconf 2.49d
seems to introduce $ac_status to hold the pre-smashed value of $?.  It'd
be nice if the documentation could get fixed to reflect this before the
2.50 release.  I spent a long time debugging a script that didn't work
as expected under autoconf 2.13 because I assumed the documentation was
correct.

Thanks,
  Bill