bsd-user: Implement System V semaphore calls

Wire up semget(2) and semop(2) syscalls to get System V semaphore
implementation, as well the undocumented __semctl used to implement the
bits of the interface in libc.

Signed-off-by: Stacey Son <sson@FreeBSD.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Warner Losh <imp@bsdimp.com>

bsd-user/freebsd/os-syscall.c

@@ -36,6 +36,7 @@
 #include "bsd-file.h"
 #include "bsd-mem.h"
 #include "bsd-proc.h"
+#include "bsd-misc.h"
 
 /* BSD dependent syscall shims */
 #include "os-stat.h"
@@ -878,6 +879,21 @@ static abi_long freebsd_syscall(void *cpu_env, int num, abi_long arg1,
         ret = do_bsd_shmdt(arg1);
         break;
 
+        /*
+         * System V Semaphores
+         */
+    case TARGET_FREEBSD_NR_semget: /* semget(2) */
+        ret = do_bsd_semget(arg1, arg2, arg3);
+        break;
+
+    case TARGET_FREEBSD_NR_semop: /* semop(2) */
+        ret = do_bsd_semop(arg1, arg2, arg3);
+        break;
+
+    case TARGET_FREEBSD_NR___semctl: { /* __semctl() undocumented */
+        ret = do_bsd___semctl(arg1, arg2, arg3, arg4);
+        break;
+    }
     case TARGET_FREEBSD_NR_freebsd11_vadvise:
         ret = do_bsd_vadvise();
         break;