Ignore-this: 8562c17c6a8cc5e34d542426d3f31b17

darcs-hash:0d1655a5d920bd2f3fb3f861aba369220830180f

Removed dependencies on portable-threads and trivial-garbage, plus minor multi-threading improvements.

darcs-hash:56b8fd98f2f784f29a7b1f62cd955a40790c5a69

darcs-hash:6f3c17c2df3eebc75ac5b2f76e0f136b62033011

darcs-hash:166b41f0885ab108410950795cee68ff4fdffe98

Another variation of making ContextL thread-safe. This time it should actually work ;), and it is again more fine-grained, that is, more efficient than the previous version.

darcs-hash:011b88f50371c2287cfd915f09bfb45b80d45feb

darcs-hash:c442d421467ec11c3072a14fd76efb7122f35609

darcs-hash:8edd57f0bc55028220ea4fff3452936b444a88e1