Issue in bison error format.

[Kaz Kylheku]

Hi all,

Errors from Bison look like this:

  parser.y:876.63: invalid character: `}'

This format differs in a small detail from the usual GCC one and so,
for instance, the Vim editor doesn't understand it; it won't jump to
the error location.

If we change it to:

  parser.y:876:63: invalid character: `}'
              ^
              colon, not dot!

then everything is cool. It now looks like a GNU C error message,
and Vim jumps to line 876, putting the cursor on the offending
closing brace.

I understand that of course this can be worked around from the editor
side. (Vim has quite a few entries in it default "errorformat" list of
patterns. Maybe a new version than what I'm using has added the
pattern for Bison.)

Still, why have, in GNU Bison, a gratuitous difference in error
reporting relative to GNU C.