Pipes cannot use SOCK_DGRAM.  Back to SOCK_STREAM.
Add debugging to fdwait.

Rewrite getcallerpc on PowerMac to be correct.
diff --git a/src/lib9/pipe.c b/src/lib9/pipe.c
index 5d0e47c..f9fe242 100644
--- a/src/lib9/pipe.c
+++ b/src/lib9/pipe.c
@@ -6,5 +6,5 @@
 int
 p9pipe(int fd[2])
 {
-	return socketpair(AF_UNIX, SOCK_DGRAM, 0, fd);
+	return socketpair(AF_UNIX, SOCK_STREAM, 0, fd);
 }