Fix option parser's long option handling

Long option names were only compared to known options based on the length
of the option name given in the arguments, resulting in strange matches,
e.g., '--step' was matching '--steps'.

Signed-off-by: Christoph Niethammer <[email protected]>

src/utils/OptionParser.cpp

@@ -216,7 +216,7 @@ const Option& OptionParser::lookup_long_opt(const std::string& opt) const {
 
 	std::list<std::string> matching;
 	for (optMap::const_iterator it = _optmap_l.begin(); it != _optmap_l.end(); ++it) {
-		if (it->first.compare(0, opt.length(), opt) == 0)
+		if (it->first == opt)
 			matching.push_back(it->first);
 	}
 	if (matching.size() > 1) {