older asciidoc prints ver into stderr

diff --git a/configure.ac b/configure.ac
index 4f25c98ffebac19170bfca6124dbae2c390d3c11..3cc28e5c5e6d04b504d343edd4fd7c81c9c28dc0 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -12,7 +12,7 @@ dnl asciidoc >= 8.2
 AC_CHECK_PROGS(ASCIIDOC, asciidoc)
 if test -n "$ASCIIDOC"; then
   AC_MSG_CHECKING([for asciidoc version >= 8.2])
-  ver=`$ASCIIDOC --version | sed 's/asciidoc //'`
+  ver=`$ASCIIDOC --version 2>&1 | sed -e 's/asciidoc //'`
   case "$ver" in
   [0-7].*|8.[01]|8.[01].*)
       AC_MSG_RESULT([$ver, too old])