thread-pool-wait-all! hangs if one of the threads is terminated.

[Takashi Kato]

This hangs:

(import (util concurrent))
(define tp (make-thread-pool 1 raise))
(thread-pool-push-task! tp (lambda () (car 'a)))
(thread-pool-wait-all! tp)

[Takashi Kato]

Handling user defined error-handler safely. (Fixes #176)

→ <<cset 08e748026a89>>