Upgrade clang to 16.0.3

We really want clang 17 for the new CUDA version, but that isn't out
yet.  This gets us a lot closer.

Change-Id: Iff6bb187260777690ae68a7eaef1e508c7194e68
Signed-off-by: Austin Schuh <austin.linux@gmail.com>
diff --git a/debian/curl.BUILD b/debian/curl.BUILD
index c6c2d2c..a4f6526 100644
--- a/debian/curl.BUILD
+++ b/debian/curl.BUILD
@@ -426,6 +426,7 @@
             "-Wno-cast-qual",
             "-Wno-format-nonliteral",
             "-Wno-tautological-type-limit-compare",
+            "-Wno-unused-but-set-variable",
         ],
     }) + select({
         ":macos": [