Chez Scheme is a complete implementation of the language of the
Revised^6 Report on Scheme (R6RS), with numerous extensions. It
sports a fast compiler that generates native code for x86, x86_64, and
32-bit PowerPC architectures. Formerly a commercial product, it was
open-sourced by Cisco Systems in April 2016.
The unthreaded version is built by default, but enabling support for
multithreading is easy:
THREADED=yes sh ./ChezScheme.SlackBuild
The full testing battery can also be run after the build completes:
TEST=yes sh ./ChezScheme.SlackBuild