IUP (software) - Wikipedia

Opinions on IUP Portable User Interface; I am looking for a simple Portable User Interface and this one was returned by Google.
Will be using it to test an embedded code project that uses a custom library that controls an Serial LCD. The embedded hardware is not always available for me to check the code I write; So, I want to be able to compile the embedded C like code and test it using a Windows PC and in later years an Linux PC. So, I will be writing a custom C library that has the same API as the embedded Serial LCD controller library that wraps around an windows UI library.

I was thinking about using SDL or SDL2; but, IUP sounds better.

The IUP Portable User Interface is a computer software development kit that provides a portable, scriptable toolkit to build graphical user interfaces (GUIs) using the programming languages C, Perl, Lua and Nim, among others.
Tim S.