Fix ambiguous call to overloaded function

(`std::exception` has a `char*` constructor?)

src/ifcparse/IfcLogger.cpp

@@ -51,7 +51,7 @@ void Logger::Message(Logger::Severity type, const std::string& message, const If
 }
 
 void Logger::Message(Logger::Severity type, const std::exception& exception, const IfcUtil::IfcBaseClass* instance) {
-	Message(type, exception.what(), instance);
+	Message(type, std::string(exception.what()), instance);
 }
 
 void Logger::Status(const std::string& message, bool new_line) {
@@ -77,4 +77,4 @@ std::ostream* Logger::log2 = 0;
 std::stringstream Logger::log_stream;
 Logger::Severity Logger::verbosity = Logger::LOG_NOTICE;
 const char* Logger::severity_strings[] = { "Notice","Warning","Error" };
-boost::optional<IfcUtil::IfcBaseClass*> Logger::current_product;
+boost::optional<IfcUtil::IfcBaseClass*> Logger::current_product;