check that driver names contain only [0-9a-z_] (nw)

src/emu/validity.cpp

@@ -1378,6 +1378,14 @@ void validity_checker::validate_driver()
 	if (is_clone && strlen(m_current_driver->name) > 16)
 		osd_printf_error("Clone driver name must be 16 characters or less\n");
 
+	// make sure the driver name doesn't contain invalid characters
+	for (const char *s = m_current_driver->name; *s != 0; s++)
+		if (((*s < '0') || (*s > '9')) && ((*s < 'a') || (*s > 'z')) && (*s != '_'))
+		{
+			osd_printf_error("Driver name contains invalid characters\n");
+			break;
+		}
+
 	// make sure the year is only digits, '?' or '+'
 	for (const char *s = m_current_driver->year; *s != 0; s++)
 		if (!isdigit((UINT8)*s) && *s != '?' && *s != '+')