Fix pthreads functions that should return ESRCH.

imgtec pointed out that pthread_kill(3) was broken, but most of the
other functions that ought to return ESRCH for invalid/exited threads
were equally broken.

Change-Id: I96347f6195549aee0c72dc39063e6c5d06d2e01f
diff --git a/libc/include/pthread.h b/libc/include/pthread.h
index ef6b80e..dbdee70 100644
--- a/libc/include/pthread.h
+++ b/libc/include/pthread.h
@@ -151,7 +151,7 @@
 
 int pthread_getschedparam(pthread_t thid, int * policy,
                           struct sched_param * param);
-int pthread_setschedparam(pthread_t thid, int poilcy,
+int pthread_setschedparam(pthread_t thid, int policy,
                           struct sched_param const * param);
 
 int pthread_mutexattr_init(pthread_mutexattr_t *attr);