This is a library of support code for programming in C on the SpiNNaker platform. It is mostly comprised of a high-performance implementation of standard fixed-point arithmetic operations, but it also includes implementations of bit-field handling, a circular buffer support library, and a random number generator (with support for various distributions).
Make sure you have the SPINN_DIRS environment variable set to the root of an installation of spinnaker_tools, that you have the relevant ARM GCC cross-compilation toolchain installed, and then do make followed by make install.