On platforms using pthreads, allow a thread to acquire a lock it already holds.  This is crucial for logging: otherwise any log message thrown from inside the logging process (especially from control.c) will deadlock.  Win32 CriticalSections are already recursive.  Bug spotted by nwf.  Bugfix on 0.2.0.16-alpha.  Backport candidate. I hope this is portable.


svn:r14406