Automatically add frameworks/rs includes to modules with .rs files

C++ sources generated from .rs files need includes in
frameworks/rs and frameworks/rs/cpp.  Add them automatically
instead of requiring modules to add them manually.

Test: builds
Change-Id: I7270fef0b36c1956475d6d83ab8aa2e3c362e688

cc/rs.go

@@ -108,7 +108,10 @@ func rsFlags(ctx ModuleContext, flags Flags, properties *BaseCompilerProperties)
 	flags.rsFlags = append(flags.rsFlags, includeDirsToFlags(rootRsIncludeDirs))
 
 	flags.GlobalFlags = append(flags.GlobalFlags,
-		"-I"+android.PathForModuleGen(ctx, "rs").String())
+		"-I"+android.PathForModuleGen(ctx, "rs").String(),
+		"-Iframeworks/rs",
+		"-Iframeworks/rs/cpp",
+	)
 
 	return flags
 }