Accept glibc 2.18 as valid.

git-svn-id: svn://svn.valgrind.org/valgrind/trunk@13504 a5019735-40e9-0310-863c-91ae7b9d1cf9
diff --git a/configure.in b/configure.in
index c51f465..58dc221 100644
--- a/configure.in
+++ b/configure.in
@@ -906,6 +906,13 @@
 	DEFAULT_SUPP="glibc-2.34567-NPTL-helgrind.supp ${DEFAULT_SUPP}"
 	DEFAULT_SUPP="glibc-2.X-drd.supp ${DEFAULT_SUPP}"
 	;;
+     2.18)
+	AC_MSG_RESULT(2.18 family)
+	AC_DEFINE([GLIBC_2_18], 1, [Define to 1 if you're using glibc 2.18.x])
+	DEFAULT_SUPP="glibc-2.X.supp ${DEFAULT_SUPP}"
+	DEFAULT_SUPP="glibc-2.34567-NPTL-helgrind.supp ${DEFAULT_SUPP}"
+	DEFAULT_SUPP="glibc-2.X-drd.supp ${DEFAULT_SUPP}"
+	;;
      darwin)
 	AC_MSG_RESULT(Darwin)
 	AC_DEFINE([DARWIN_LIBC], 1, [Define to 1 if you're using Darwin])