To build, extract the desired Glk implementation into the top level directory.
The Glk implementation must have its own copy of CMakeLists.txt which exports a
target called “glk” which represents the Glk library. CMakeLists.txt files are
provided for the following Glk implementations:

cheapglk
glkterm
glktermw
remglk
xglk
nanoglk

These are all avaialble from http://www.eblong.com/zarf/glk/ with the exception
of nanoglk which is available from
http://www.ifarchive.org/indexes/if-archiveXprogrammingXglkXimplementations.html.

CMake is used to build the interpreters. Set the GLK variable to whichever Glk
implementation you would like to build against, e.g.:

$ mkdir build
$ cd build
$ cmake .. -DGLK=glktermw
$ make

This will build both the Glk implementation and all included interpreters.