More verbose AC_TRY_RUN

[Akim Demaille]

A friend of mine had problems with AC_HEADER_STDC and it was
impossible, reading the logs, to understand what went wrong.
AC_TRY_RUN is not verbose enough.

Index: ChangeLog
from  Akim Demaille  <address@hidden>
        Let AC_TRY_RUN be more verbose

        * acgeneral.m4 (_AC_RUN_IFELSE): Instead of canceling the output
        of the test program, save it into the log.
        Save the exit status, and report it in the log when non zero.
        Just use `(./conftest)' instead of `(./conftest; exit)'.

Index: acgeneral.m4
===================================================================
RCS file: /cvs/autoconf/acgeneral.m4,v
retrieving revision 1.629
diff -u -u -r1.629 acgeneral.m4
--- acgeneral.m4 2000/11/14 11:06:37 1.629
+++ acgeneral.m4 2000/11/16 17:58:32
@@ -2884,14 +2884,15 @@
 m4_define([_AC_RUN_IFELSE],
 [m4_ifvanl([$1], [AC_LANG_CONFTEST([$1])])dnl
 rm -f conftest$ac_exeext
-if AC_TRY_EVAL(ac_link) &&
-   test -s conftest$ac_exeext && (./conftest$ac_exeext; exit) 2>/dev/null; then
-  m4_default([$2], :)
-else
-  echo "$as_me: failed program was:" >&AS_MESSAGE_LOG_FD
-  cat conftest.$ac_ext >&AS_MESSAGE_LOG_FD
-m4_ifvanl([$3], [  $3])dnl
-fi
+AC_TRY_EVAL(ac_link) &&
+  (./conftest$ac_exeext) >&AS_MESSAGE_LOG_FD 2>&1;
+ac_status=$?
+AS_IFELSE([test $ac_status == 0],
+          [$2],
+[echo "$as_me: program exited with status: $ac_status" >&AS_MESSAGE_LOG_FD
+echo "$as_me: failed program was:" >&AS_MESSAGE_LOG_FD
+cat conftest.$ac_ext >&AS_MESSAGE_LOG_FD[]dnl
+m4_ifvanl([$3], [$3])])
 rm -f conftest$ac_exeext ifval([$1], [conftest.$ac_ext])[]dnl
 ])# _AC_RUN_IFELSE