What license info needed when posting a GitHub project using GMP?

[Otto van Verseveld]

I'm about to post my very first GitHub OSX/Xcode based project with some
code using the latest libgmp.h and libgmp.a library which I compiled on my
MacMini with MacOSX 10.9 and Xcode 6.1.

What do I need to add, in terms of (references) to GMP license-agreement,
as additional info in the About / ReadMe description of my GitHub
repository?

Anybody (references to) a standard template or format I can (re)use?

Thanks very much in advance!