Rename ninja variables with Clang in the name

Rename the ninja variables that have an extraneous Clang in the name,
since there are no longer any non-Clang variables.

Bug: 68947919
Test: no change to command lines used to build mmma bionic
Change-Id: I081d5e1d423a66d55faece6cb1d265cd5e504d5f
diff --git a/cc/compiler.go b/cc/compiler.go
index 81ac035..b01ba43 100644
--- a/cc/compiler.go
+++ b/cc/compiler.go
@@ -438,14 +438,14 @@
 	flags.Global.CppFlags = append([]string{fmt.Sprintf("${config.%sGlobalCppflags}", hod)}, flags.Global.CppFlags...)
 
 	flags.Global.AsFlags = append(flags.Global.AsFlags, tc.Asflags())
-	flags.Global.CppFlags = append([]string{"${config.CommonClangGlobalCppflags}"}, flags.Global.CppFlags...)
+	flags.Global.CppFlags = append([]string{"${config.CommonGlobalCppflags}"}, flags.Global.CppFlags...)
 	flags.Global.CommonFlags = append(flags.Global.CommonFlags,
 		tc.Cflags(),
-		"${config.CommonClangGlobalCflags}",
-		fmt.Sprintf("${config.%sClangGlobalCflags}", hod))
+		"${config.CommonGlobalCflags}",
+		fmt.Sprintf("${config.%sGlobalCflags}", hod))
 
 	if isThirdParty(modulePath) {
-		flags.Global.CommonFlags = append(flags.Global.CommonFlags, "${config.ClangExternalCflags}")
+		flags.Global.CommonFlags = append(flags.Global.CommonFlags, "${config.ExternalCflags}")
 	}
 
 	if tc.Bionic() {