Changeset 65c421f in rtems

default thread attributes: default value for inheritsched changed from
explicit to inherit scheduler to be consistent with FSU pthreads for gnat.

_POSIX_Threads_Create_extension: now inherit signal blocked mask from
creator if the new thread is a posix thread.

_POSIX_Threads_Initialize_user_threads: make sure posix initialization
threads start with a useful priority. If they inherit the priority
of the creating thread, they will end up at the same priority as the
idle thread. Since the idle thread does not yield, they will not run.