Reflect latest interface changes; return 0 on success and -1 on error.

sysdeps/linux/shm_limits.c

@@ -37,6 +37,8 @@ int
 glibtop_init_shm_limits_s (glibtop *server)
 {
 	server->sysdeps.shm_limits = _glibtop_sysdeps_shm_limits;
+
+	return 0;
 }
 
 /* Provides information about sysv ipc limits. */
@@ -59,4 +61,6 @@ glibtop_get_shm_limits_s (glibtop *server, glibtop_shm_limits *buf)
 	buf->shmmni = shminfo.shmmni;
 	buf->shmseg = shminfo.shmseg;
 	buf->shmall = shminfo.shmall;
+
+	return 0;
 }