libnix is a static (i.e. link) library for usage on amiga computers together with gcc 2.3.3 or above. It is very amigalike and contains a lot of features you probably don't want to miss:
So if you want to write amiga specific programs or if you only need ANSI support instead of unix compatibility - and if you don't want to redistribute ixemul.library - this can be your choice.
But be aware - libnix requires Amiga OS 2.0 or higher :(.