This is possible, but means quite some work. First, you need all the X11 and gtk libraries, probably from a package manager like fink, macports or homebrew. All the libraries, which are not part of default macOS, will need to be put in the application bundle with their install names adjusted to the new location. I did this with the 20 or so libraries for a standalone application bundle of ultra star deluxe, a karaoke game. You will find it on sourceforge. The Makefile contains script parts to build the application bundles. In summary: It is definitely possible and one can even create a script for it, but it is involved. I am not sure about the current state of the script, but it shows at least the way to go. I can give you some more detailed instructions, if needed.