(_AC_PREPROC_IFELSE, _AC_COMPILE_IFELSE,

_AC_LINK_IFELSE): Redirect stdin to /dev/null, in an attempt to
avoid thinking that Allegro Common Lisp's "cl" command is a C++
compiler.

diff --git a/lib/autoconf/general.m4 b/lib/autoconf/general.m4
index 430441a525e1b4de83a249d33657f2d5ae9ab8ae..7af2f2869d6969fafb5abc79bb2a030a5be10ca4 100644 (file)
--- a/lib/autoconf/general.m4
+++ b/lib/autoconf/general.m4
@@ -2133,7 +2133,7 @@ AC_DEFUN([AC_RUN_LOG],
 # to expand ac_cpp.
 AC_DEFUN([_AC_PREPROC_IFELSE],
 [m4_ifvaln([$1], [AC_LANG_CONFTEST([$1])])dnl
-if _AC_EVAL_STDERR([$ac_cpp conftest.$ac_ext]) >/dev/null; then
+if _AC_EVAL_STDERR([$ac_cpp conftest.$ac_ext]) </dev/null >/dev/null; then
   if test -s conftest.err; then
     ac_cpp_err=$ac_[]_AC_LANG_ABBREV[]_preproc_warn_flag
     ac_cpp_err=$ac_cpp_err$ac_[]_AC_LANG_ABBREV[]_werror_flag
@@ -2218,7 +2218,7 @@ AC_DEFUN([AC_EGREP_HEADER],
 m4_define([_AC_COMPILE_IFELSE],
 [m4_ifvaln([$1], [AC_LANG_CONFTEST([$1])])dnl
 rm -f conftest.$ac_objext
-AS_IF([_AC_EVAL_STDERR($ac_compile) &&
+AS_IF([_AC_EVAL_STDERR($ac_compile) </dev/null &&
         AC_TRY_COMMAND([test -z "$ac_[]_AC_LANG_ABBREV[]_werror_flag"
                         || test ! -s conftest.err]) &&
         AC_TRY_COMMAND([test -s conftest.$ac_objext])],
@@ -2259,7 +2259,7 @@ AU_DEFUN([AC_TRY_COMPILE],
 m4_define([_AC_LINK_IFELSE],
 [m4_ifvaln([$1], [AC_LANG_CONFTEST([$1])])dnl
 rm -f conftest.$ac_objext conftest$ac_exeext
-AS_IF([_AC_EVAL_STDERR($ac_link) &&
+AS_IF([_AC_EVAL_STDERR($ac_link) </dev/null &&
         AC_TRY_COMMAND([test -z "$ac_[]_AC_LANG_ABBREV[]_werror_flag"
                         || test ! -s conftest.err]) &&
         AC_TRY_COMMAND([test -s conftest$ac_exeext])],