openvt: fix gross mismatch between us and "standard" openvt.

  standard one even has different syntax!
  std: "openvt -c 12", we: "openvt 12"
  std: "openvt top", we: complain that "top" is not a number.
openvt: implement -c -w -s (-l -f -v are also accepted but ingnored)

openvt_main                                          188     343    +155
vfork_child                                            -      67     +67
not_vt_fd                                              -      23     +23
packed_usage                                       23932   23952     +20
------------------------------------------------------------------------------
(add/remove: 2/0 grow/shrink: 2/0 up/down: 265/0)             Total: 265 bytes
   text    data     bss     dec     hex filename
 801344     641    7380  809365   c5995 busybox_old
 801617     641    7380  809638   c5aa6 busybox_unstripped

1 files changed, 8 insertions, 2 deletions

diff --git a/include/usage.h b/include/usage.h
index f950a0a49..3be317bff 100644
--- a/include/usage.h
+++ b/include/usage.h
@@ -2818,9 +2818,15 @@
        "to standard output. With no FILE or when FILE is -, read standard input."
 
 #define openvt_trivial_usage \
-       "VTNUM COMMAND [ARGS...]"
+       "[-c NUM] [-sw] [COMMAND [ARGS]]"
 #define openvt_full_usage \
-       "Start a command on a new virtual terminal"
+       "Start COMMAND on a new virtual terminal\n" \
+     "\nOptions:" \
+     "\n        -c      Use specified VT" \
+     "\n        -s      Switch to the VT" \
+/*   "\n        -l      Run COMMAND as login shell (by prepending '-')" */ \
+     "\n        -w      Wait for COMMAND to exit" \
+
 #define openvt_example_usage \
        "openvt 2 /bin/ash\n"