autoconf 2.52 fails to detect compiler output under GNV on OpenVMS

[Eric Sharkey]

On my OpenVMS 7.1 system, the DEC C 5.5 compiler when called through
a GNV (gnv.sourceforge.net) cc wrapper, produces the output file named
"a_out.exe", which is not detected by configure scripts generated by
autoconf 2.52.  This patch fixes it.

Eric Sharkey
<address@hidden>
<address@hidden>

box% diff -c aclang.m4.org aclang.m4     
*** aclang.m4.org       Sun Oct  7 18:13:17 2001
--- aclang.m4   Sun Oct  7 18:14:26 2001
***************
*** 665,670 ****
--- 665,671 ----
  # resort.
  for ac_file in `ls a.exe conftest.exe 2>/dev/null;
                  ls a.out conftest 2>/dev/null;
+                 ls a_out.exe 2>/dev/null;
                  ls a.* conftest.* 2>/dev/null`; do
    case $ac_file in
      *.$ac_ext | *.o | *.obj | *.xcoff | *.tds | *.d | *.pdb ) ;;