pkg_delete and modified files

[Andrew Pantyukhin]

Looking for a solution to the problem we stumbled upon,
[which was keeping many modified files without the
cmp trick described in the porter's handbook]
I gave pkg_install/* sources a glance and now I'm
thinking about a quick fix. The -f flag causes files to be
deleted even in case of a checksum mismatch. In fact
the -f flag is meant for something slightly else:

Force removal of the package, even if a dependency
is recorded or the deinstall or require script fails.

So I'm thinking about another flag (like -F or a second
-f) to control the behavior with modified files. I think that
keeping them should be a default. I can't think of a
thing that it will break, maybe you can. The cmp trick
will still work. And it only takes a couple of lines to
implement.