diff --git a/cc/config/clang.go b/cc/config/clang.go
index 64bb96e..6f08fa9 100644
--- a/cc/config/clang.go
+++ b/cc/config/clang.go
@@ -97,6 +97,12 @@
 		// http://b/29823425 Disable -Wexpansion-to-defined for Clang update to r271374
 		"-Wno-expansion-to-defined",
 
+		// http://b/68236239 Allow 0/NULL instead of using nullptr everywhere.
+		"-Wno-zero-as-null-pointer-constant",
+
+		// http://b/68236396 Allow unknown warning options.
+		"-Wno-unknown-warning-option",
+
 		// http://b/36463318 Clang executes with an absolute path, so clang-provided
 		// headers are now absolute.
 		"-fdebug-prefix-map=$$PWD/=",
diff --git a/cc/config/global.go b/cc/config/global.go
index e9f5473..dae218c 100644
--- a/cc/config/global.go
+++ b/cc/config/global.go
@@ -77,8 +77,8 @@
 
 	// prebuilts/clang default settings.
 	ClangDefaultBase         = "prebuilts/clang/host"
-	ClangDefaultVersion      = "clang-4053586"
-	ClangDefaultShortVersion = "5.0"
+	ClangDefaultVersion      = "clang-4393122"
+	ClangDefaultShortVersion = "5.0.1"
 )
 
 var pctx = android.NewPackageContext("android/soong/cc/config")