diff --git a/configure b/configure
index d62ffa838c9..76616170195 100755
--- a/configure
+++ b/configure
@@ -4214,7 +4214,7 @@ cat >conftest.l <<EOF
 }
 %%
 EOF
-if $FLEX -t conftest.l >/dev/null 2>&1
+if $FLEX -t conftest.l >/dev/null 2>&5
 then
   { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
 $as_echo "yes" >&6; }
diff --git a/configure.ac b/configure.ac
index b7373b202c5..5ba22c41e7e 100644
--- a/configure.ac
+++ b/configure.ac
@@ -243,7 +243,7 @@ cat >conftest.l <<EOF
 }
 %%
 EOF
-if $FLEX -t conftest.l >/dev/null 2>&1
+if $FLEX -t conftest.l >/dev/null 2>&AS_MESSAGE_LOG_FD
 then
   AC_MSG_RESULT([yes])
 else