Portable threads library for Common Lisp

 BORDEAUX-THREADS is a proposed standard for a minimal MP/Threading interface.
 .
 It essentially provides a compatibility layer for multi-threading across
 multiple CL implementations.
 .
 Some parts of its implementation-specific code can also be implemented in a
 Lisp that does not support multiple threads, so that thread-safe code can be
 compiled on both multithread and single-thread implementations without need of
 conditionals.