Previously, the RefC files were located in IDRIS2_PREFIX. This is
decoupled to allow users to change the prefix (for ad-hoc library
install locations, for example).
Written by Volkmar Frinken (@vfrinken). This is intended as a
lightweight (i.e. minimal dependencies) code generator that can be
ported to multiple platforms, especially those with memory constraints.
It shouldn't be expected to be anywhere near as fast as the Scheme back
end, for lots of reasons. The main goal is portability.