patch(1): Add -Vnone option to disable backup files

[cem]

Test Plan

Manually applied patches with -Vnone, observed that .orig files were not
spammed throughout my tree.

[pfg]

Thank you.

FWIW, NetBSD added the same option 15 months ago:

http://cvsweb.netbsd.org/bsdweb.cgi/src/usr.bin/patch/

Perhaps we can reduce the differences? It helps to be able to merge changes from elsewhere.

[cem]

In D3146#62739, @pfg wrote:

Thank you.

FWIW, NetBSD added the same option 15 months ago:

http://cvsweb.netbsd.org/bsdweb.cgi/src/usr.bin/patch/

Perhaps we can reduce the differences? It helps to be able to merge changes from elsewhere.

Hah, and we even spelled it mostly the same. Sure, I can try and make the diff smaller.

[cem]

I think -Vnone is broken in NetBSD. In particular, they override none in main() after parsing the switch:

	/* parse switches */
	Argc = argc;
	Argv = argv;
	get_some_switches();

	if (backup_type == none) {
		if ((v = getenv("PATCH_VERSION_CONTROL")) == NULL)
			v = getenv("VERSION_CONTROL");
		if (v != NULL || !posix)
			backup_type = get_version(v);	/* OK to pass NULL. */
	}

And they are missing -Vnone in usage().

[cem]

Reorder backup_args / backup_types to diff-reduce vs NetBSD

[pfg]

In D3146#62741, @cem wrote:

I think -Vnone is broken in NetBSD. In particular, they override none in main() after parsing the switch:

Heh .. now I recall I was going to merge their change but something looked broken :-P.
It's alright though, I just wanted to see some diff reduction. Our patch(1) is already a fork on it's own but it also has changes from all the other BSDs.

[cem]

In D3146#62748, @pfg wrote:

Heh .. now I recall I was going to merge their change but something looked broken :-P.
It's alright though, I just wanted to see some diff reduction. Our patch(1) is already a fork on it's own but it also has changes from all the other BSDs.

Sure, no problem. Thanks for the quick review!