(ITS#4349) hang in ldap_pvt_thread_pool_destroy()

[hyc@OpenLDAP.org]

Full_Name: Howard Chu
Version: HEAD,2.3.18
OS: 
URL: ftp://ftp.openldap.org/incoming/
Submission from: (NULL) (24.126.120.178)
Submitted by: hyc


The ldap_pvt_thread_pool_destroy() function will hang if there were no threads
in the thread pool. It broadcasts on a condition variable and waits for the last
exiting thread to signal it back, but there are no other threads so it will wait
forever. This was a caused by some of the rework for ITS#3950. The fix is
trivial, coming up.

This bug will only show up when trying to kill a freshly started server; once a
request has been received and at least one job has been submitted to the thread
pool, everything is fine.