vi: fix backward search with GNU regex

With FEATURE_VI_REGEX_SEARCH enabled backward searches don't work.
This is problematic on distros that enable regexes, such as Tiny
Core Linux and Fedora.

When calling GNU re_search() with a negative range parameter
(indicating a backward search) the start offset must be set to
the end of the area being searched.

The return value of re_search() is the offset of the matched pattern
from the start of the area being searched.  For a successful search
(positive return value) char_search() can return the pointer to
the start of the area plus the offset.

FEATURE_VI_REGEX_SEARCH isn't enabled by default but when it is:

function                                             old     new   delta
char_search                                          256     247      -9
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-9)               Total: -9 bytes

Signed-off-by: Andrey Dobrovolsky <andrey.dobrovolsky.odessa@gmail.com>
Signed-off-by: Ron Yorston <rmy@pobox.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

0 files changed, 0 insertions, 0 deletions