Roll Clang toolchain

Change-Id: I2e87d3d368bf22097d80ddf695f67284b444d025
diff --git a/fuchsia.ensure b/fuchsia.ensure
index 24fd295..8307e3c 100644
--- a/fuchsia.ensure
+++ b/fuchsia.ensure
@@ -35,7 +35,7 @@
 
 # Clang
 @Subdir clang
-fuchsia/clang/${platform} git_revision:4c6142e3bc986b79dc0f7c9deafc82af13eab12f
+fuchsia/clang/${platform} git_revision:4ad2908c9b4b485a0bf683f62a68e22f040b9f61
 
 # Go
 @Subdir go