You can install this wrapper using the Nimble package manager.
nimble install gtk2 # To install latest tagged version from git, if one exists.
nimble install gtk2#head # To install GIT HEAD.
If you wish to add this wrapper as a dependency to your nimble package then add the following to your .nimble file.
[Deps]
Requires = "gtk2#head"
As of version 1.1 this binding will use GTK-Quartz if it is available, otherwise it will fallback to the X11 version of GTK.