Add -v (-verbose/--verbose) option to llvm-rs-cc.

This change also suppresses the display of "Generating Script*." output by
default.

Change-Id: I034a3ba20acf64e1eb9ecc02133edb03b643d559
diff --git a/RSCCOptions.td b/RSCCOptions.td
index 1f56cdc..1d5f536 100644
--- a/RSCCOptions.td
+++ b/RSCCOptions.td
@@ -123,6 +123,11 @@
 // Misc Options
 //===----------------------------------------------------------------------===//
 
+def verbose : Flag<["-"], "v">,
+  HelpText<"Display verbose information during the compilation">;
+def _verbose : Flag<["-"], "verbose">, Alias<verbose>;
+def __verbose : Flag<["--"], "verbose">, Alias<verbose>;
+
 def help : Flag<["-"], "help">,
   HelpText<"Print this help text">;
 def _help : Flag<["--"], "help">, Alias<help>;