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/slang_rs_context.h b/slang_rs_context.h
index cdb35c6..3373a8b 100644
--- a/slang_rs_context.h
+++ b/slang_rs_context.h
@@ -68,6 +68,7 @@
   clang::ASTContext &mCtx;
   PragmaList *mPragmas;
   unsigned int mTargetAPI;
+  bool mVerbose;
 
   llvm::DataLayout *mDataLayout;
   llvm::LLVMContext &mLLVMContext;
@@ -102,7 +103,8 @@
             clang::ASTContext &Ctx,
             const clang::TargetInfo &Target,
             PragmaList *Pragmas,
-            unsigned int TargetAPI);
+            unsigned int TargetAPI,
+            bool Verbose);
 
   inline clang::Preprocessor &getPreprocessor() const { return mPP; }
   inline clang::ASTContext &getASTContext() const { return mCtx; }
@@ -121,6 +123,10 @@
     return mTargetAPI;
   }
 
+  inline bool getVerbose() const {
+    return mVerbose;
+  }
+
   inline void setLicenseNote(const std::string &S) {
     mLicenseNote = new std::string(S);
   }