#65 Add history support for xcscope.el

[lgfang]

I modified xcscope.el for browsing cscope result history. Attached file is 'diff -cb' with xcscope.el come with cscope-15.6.

I think the primary benefit of this feature is to give us a clue how we gotten into current position. I used to ask myself “how I get into function?” since the code I’m reading has really deep call stacks and I can’t keep them all in my mind. The other benefit is that, for large projects, cscope-ing sometimes could be time-consuming.

USAGE:

To view previous search result, call cscope-history-backward (‘C-c s v’ or just ‘v’ in cscope buffer) or cscope-history-forward (‘V’). To discard cscope history, M-x cscope-history-clear To delete history entry currently visiting, M-x cscope-history-delete

[lgfang]

diff -cb xcscope.el.from-cscope15.6 xcscope.history.el > xcscope.hist.patch