Fixed some warnings in libc

diff --git a/modules/libc b/modules/libc
index c5c3aecf3f5340b19cffe4fc3a42bfbe8cd2efc6..71188357ccc74a381f48d4747a2e4a8fedb1626b 160000 (submodule)
--- a/modules/libc
+++ b/modules/libc
@@ -1 +1 @@
-Subproject commit c5c3aecf3f5340b19cffe4fc3a42bfbe8cd2efc6
+Subproject commit 71188357ccc74a381f48d4747a2e4a8fedb1626b