slackbuilds/development/mono

Mono is a software platform designed to allow developers to easily create 
cross platform applications.  It is an open source implementation of 
Microsoft's .Net Framework based on the ECMA standards for C# and the Common 
Language Runtime.  We feel that by embracing a successful, standardized 
software platform, we can lower the barriers to producing great applications 
for Linux.

This requires libgdiplus.