... and set $(BOOST_LIBS) properly again.

git-svn-id: svn://svn.valgrind.org/valgrind/trunk@12508 a5019735-40e9-0310-863c-91ae7b9d1cf9
diff --git a/configure.in b/configure.in
index 177e58a..df7be3d 100644
--- a/configure.in
+++ b/configure.in
@@ -1885,7 +1885,7 @@
 [
 ac_have_boost_1_35=yes
 AC_SUBST([BOOST_CFLAGS], [])
-AC_SUBST([BOOST_LIBS], ["${CXXFLAGS}"])
+AC_SUBST([BOOST_LIBS], [-lboost_thread-mt])
 AC_MSG_RESULT([yes])
 ], [
 ac_have_boost_1_35=no