Maybe you don't have any audio software. If you can't find audio include files/libraries that's a good bet.
Irix 5.3 includes the audio package as a default again. If you were using
Irix 5.2 or lower, upgrade. If you are using Irix 5.3, check that the audio
has been installed.
Also, the standard sgi `make' is crippled. See Generic problems.
If the audio output sounds like garbage, you probably botched the `typedef'
of SAMPLE. Chars on Silicon Graphics are unsigned by default, and
SAMPLE needs to be signed char
[1].
This can happen very easily if the `config.h' tracker uses is not the
Silicon Graphics one. Remove the `config.h' in the main directory,
and let make replace it with the correct one.
[1] I have not put this in every `config.h' for compatibility with old K&R compilers