PR 1855/cpukit
* posix/src/psignal.c, posix/src/psignalunblockthread.c,
posix/src/pthread.c, posix/src/pthreadjoin.c: Correct signal
processing during pthread_join. We are supposed to unblock the thread
waiting on a pthread_join(), dispatch the signal handler, account for
it potentially overwriting errno, and then have the thread return to
blocking within pthread_join().
426eb35f03