build: update gnulib submodule to latest

diff --git a/gnulib b/gnulib
index 880a2f6db9e37ef84347a47b15f88bef741c03da..d4cecf1ee37f6b611ef092c9c7fa3761d02ce2c3 160000 (submodule)
--- a/gnulib
+++ b/gnulib
@@ -1 +1 @@
-Subproject commit 880a2f6db9e37ef84347a47b15f88bef741c03da
+Subproject commit d4cecf1ee37f6b611ef092c9c7fa3761d02ce2c3