Update gnulib to fix building on OSX 10.9

Fixes #926

Signed-off-by: Tim Rühsen <tim.ruehsen@gmx.de>

diff --git a/gnulib b/gnulib
index 07fb4954db5032be9c61af7e014521efb6f7d207..02c8a3da2c4462ecf78944af9f6fd2c986fa536c 160000 (submodule)
--- a/gnulib
+++ b/gnulib
@@ -1 +1 @@
-Subproject commit 07fb4954db5032be9c61af7e014521efb6f7d207
+Subproject commit 02c8a3da2c4462ecf78944af9f6fd2c986fa536c