[Ecls-list] Improvements in threads

[Juan Jose Garcia-Ripoll]

* New features:

 - ECL now has POSIX condition variables when built with threads. Moreover,
   locks can be now recursive or non-recursive, that is, the kind that signals
   an error when tried to grabed twice from the same thread (Dan Corkill).

Thanks do Dan for the patches that allow this. Note however that the
windows part is yet incomplete: the code for implementing something
like POSIX condition variables is missing, but the
recursive/error-checking locks are already there.

Juanjo

-- 
Facultad de Fisicas, Universidad Complutense,
Ciudad Universitaria s/n Madrid 28040 (Spain)
http://juanjose.garciaripoll.googlepages.com