This Howto assumes a build environment of custom firmware 126.96.36.199-4 has been setup according to the instructions provided in Oleg's page of "ASUS WL-500g custom firmware page". It should also work for other versions, but it is not tested.
ASUS firmware build package do not come with all the libraries required by madplay, therefore it must build and install them by yourself.
Warning: Below instructions will install additional libraries under the toolchain's path.
(This environment variable is not really necessary in the build process. It is used to indicate the target installation path that passes to configure script.)
After installed all the libraries provided above, you could now compile madplay:
If no error was found during the compilation, a binary file (`madplay`) should be created within the path of madplay-0.15.2b/ . As additional libraries like libmad and id3tag are linked statically, you could just install this single binary to your access point.