libc: Add missing pipe2() declaration and implementation.

Change-Id: Iacb914bd6ac5adc60c5671e6fef680ede21f9b0c
diff --git a/libc/SYSCALLS.TXT b/libc/SYSCALLS.TXT
index f66ff40..4bcccb5 100644
--- a/libc/SYSCALLS.TXT
+++ b/libc/SYSCALLS.TXT
@@ -112,6 +112,7 @@
 int         fchmod(int, mode_t)  94
 int         dup(int)  41
 int         pipe(int *)  42,42,-1
+int         pipe2(int *, int) 359,331
 int         dup2(int, int)   63
 int         select:_newselect(int, struct fd_set *, struct fd_set *, struct fd_set *, struct timeval *)  142
 int         ftruncate(int, off_t)  93
@@ -229,8 +230,8 @@
 int sched_rr_get_interval(pid_t pid, struct timespec *interval)  161
 
 # io priorities
-int ioprio_set(int which, int who, int ioprio) 314,289
-int ioprio_get(int which, int who) 315,290
+int ioprio_set(int which, int who, int ioprio) 314,289,288
+int ioprio_get(int which, int who) 315,290,289
 
 # other
 int     uname(struct utsname *)  122