vi: fix buffer overrun; code shrink

It was possible for get_input_line() to store its NUL terminator
one character beyond the end of its buffer.

Code shrink in colon():

- Certain colon commands can be matched exactly, as any shorter
  string would be matched earlier, e.g. ':wq' versus ':write'.

- Command matching is now case sensitive so there's no need to
  check for 'N' or 'Q' suffixes.

- Rewrite how commands and arguments are split.

function                                             old     new   delta
colon                                               3848    3751     -97
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-97)             Total: -97 bytes

Signed-off-by: Ron Yorston <rmy@pobox.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
1 file changed