ENH: CheckOptions now takes const argv.

Source/cmDocumentation.cxx

@@ -222,7 +222,7 @@ bool cmDocumentation::PrintRequestedDocumentation(std::ostream& os)
 }
 
 //----------------------------------------------------------------------------
-bool cmDocumentation::CheckOptions(int argc, char** argv)
+bool cmDocumentation::CheckOptions(int argc, const char* const* argv)
 {
   // Providing zero arguments gives usage information.
   if(argc == 1)

Source/cmDocumentation.h

@@ -36,7 +36,7 @@ public:
    * When true is returned, PrintRequestedDocumentation should be
    * called.
    */
-  bool CheckOptions(int argc, char** argv);
+  bool CheckOptions(int argc, const char* const* argv);
   
   /**
    * Print help requested on the command line.  Call after