libromfs-ogc is a port of libromfs-wiiu to the Wii and Gamecube.
To install the library:
Wii
$ git clone https://github.com/NateXS/libromfs-ogc.git
$ cd libromfs-ogc
$ make PLATFORM=wii
$ (sudo -E) make PLATFORM=wii install
Gamecube
$ git clone https://github.com/NateXS/libromfs-ogc.git
$ cd libromfs-ogc
$ make PLATFORM=gamecube
$ (sudo -E) make PLATFORM=gamecube install