Fix test for Boost version / presence

BOOST_GOT_VERSION might be "" on new GCCs.

diff --git a/boost.m4 b/boost.m4
index bffcf4a..0540465 100644 (file)
--- a/boost.m4
+++ b/boost.m4
@@ -57,7 +57,8 @@ AC_DEFUN([ID_BOOST],
 version_is:BOOST_VERSION
 ]])])
            BOOST_GOT_VERSION=`(eval "$ac_cpp conftest.$ac_ext") 2>&AS_MESSAGE_LOG_FD | $EGREP version_is 2>/dev/null | cut -d ":" -f2`
-           if test "$BOOST_GOT_VERSION" = "BOOST_VERSION"; then
+           if test -z "$BOOST_GOT_VERSION" -o \
+               "$BOOST_GOT_VERSION" = "BOOST_VERSION"; then
                AC_MSG_RESULT([no])
                AC_MSG_ERROR([Boost development libraries required])
            fi