Switch to clang-4393122.

Bug: http://b/62580008
Bug: http://b/68236239
Bug: http://b/68236396
Test: https://goto.google.com/clang-4393122-testing
Change-Id: Ib6bcf93e356172aad2a762b730a6f93916a5d845

cc/config/clang.go

@@ -97,6 +97,12 @@ func init() {
 		// 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/=",

cc/config/global.go

@@ -77,8 +77,8 @@ var (
 
 	// 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")