Modify mount(8) to skip MNT_IGNORE file systems by default, just like df(1)

does. This is not POLA violation, because there is no single file system in the
base that use MNT_IGNORE currently, although ZFS snapshots will be mounted with
MNT_IGNORE after next commit.

Reviewed by:	kib
MFC after:	3 days

sbin/mount/mount.8

@@ -469,6 +469,12 @@ or
 option.
 .It Fl v
 Verbose mode.
+If the
+.Fl v
+is used alone, show all file systems, including those that were mounted with the
+.Dv MNT_IGNORE
+flag and show additional information about each file system (including fsid
+when run by root).
 .It Fl w
 The file system object is to be read and write.
 .El

sbin/mount/mount.c

@@ -348,6 +348,9 @@ main(int argc, char *argv[])
 				if (checkvfsname(mntbuf[i].f_fstypename,
 				    vfslist))
 					continue;
+				if (!verbose &&
+				    (mntbuf[i].f_flags & MNT_IGNORE) != 0)
+					continue;
 				prmount(&mntbuf[i]);
 			}
 		}