gvc: Fix some memory leaks

diff --git a/src/gvc b/src/gvc
index 25bf3ed75fa604fa73e8b25241119a993fc659d6..ce8e4880ce31e275c40825c4ed756c791107f810 160000 (submodule)
--- a/src/gvc
+++ b/src/gvc
@@ -1 +1 @@
-Subproject commit 25bf3ed75fa604fa73e8b25241119a993fc659d6
+Subproject commit ce8e4880ce31e275c40825c4ed756c791107f810