Flesh out <sys/msg.h>, <sys/sem.h>, <sys/shm.h>.

Also fix <sys/ipc.h>.

Not useful except to systems/bringup folks for testing. Trivial tests
added, and double-checked under strace to see that things look right.

x86 -- which works differently to everything else -- tested on the host.

Bug: http://b/27952303
Change-Id: I328534e994ae9e90755f545478fba03038c0bb94
diff --git a/libc/libc.arm.map b/libc/libc.arm.map
index 1cff815..c4243f4 100644
--- a/libc/libc.arm.map
+++ b/libc/libc.arm.map
@@ -1284,11 +1284,23 @@
     hasmntopt; # future
     lutimes; # future
     mblen; # future
+    msgctl; # future
+    msgget; # future
+    msgrcv; # future
+    msgsnd; # future
     pthread_getname_np; # future
     quotactl; # future
+    semctl; # future
+    semget; # future
+    semop; # future
+    semtimedop; # future
     setdomainname; # future
     setgrent; # future
     setpwent; # future
+    shmat; # future
+    shmctl; # future
+    shmdt; # future
+    shmget; # future
     sighold; # future
     sigignore; # future
     sigpause; # future