Update LLVM. Fixes for segmented stacks with fastcc functions

diff --git a/src/llvm b/src/llvm
index dc6b4306ad94ccaa6e400160e3e5ef33abff2f99..80c896f8ad46f5c3fb777c32c0c71d58a4bdb1e7 160000 (submodule)
--- a/src/llvm
+++ b/src/llvm
@@ -1 +1 @@
-Subproject commit dc6b4306ad94ccaa6e400160e3e5ef33abff2f99
+Subproject commit 80c896f8ad46f5c3fb777c32c0c71d58a4bdb1e7