cpack: Fail-fast on unknown arguments

Source/CPack/cpack.cxx

@@ -253,14 +253,21 @@ int main(int argc, char const* const* argv)
   bool parsed = true;
   for (std::size_t i = 0; i < inputArgs.size(); i++) {
     auto const& arg = inputArgs[i];
+    bool matched = false;
     for (auto const& m : arguments) {
       if (m.matches(arg)) {
+        matched = true;
         if (!m.parse(arg, i, inputArgs, &cminst, &globalMF)) {
           parsed = false;
         }
         break;
       }
     }
+    if (!matched && cmHasPrefix(arg, '-')) {
+      std::string error = cmStrCat("Unknown argument: ", arg);
+      cmCPack_Log(&log, cmCPackLog::LOG_ERROR, error << '\n');
+      parsed = false;
+    }
   }
 
   cmCPackGeneratorFactory generators;