Add "const". And clean up.

Change-Id: I70e6994a0cd1d897e6981d5642108fee1324708f
diff --git a/lib/ExecutionEngine/ScriptCompiled.h b/lib/ExecutionEngine/ScriptCompiled.h
index f7bf48b..5da8851 100644
--- a/lib/ExecutionEngine/ScriptCompiled.h
+++ b/lib/ExecutionEngine/ScriptCompiled.h
@@ -85,7 +85,7 @@
       return mCompiler.linkModule(module);
     }
 
-    int compile(CompilerOption &option) {
+    int compile(const CompilerOption &option) {
       return mCompiler.compile(option);
     }