PATCH: widl: implement move-if-changed logic

[Marcus Meissner]

On Thu, Sep 03, 2015 at 06:54:05PM +0200, Jacek Caban wrote:
> Hi Marcus,
> 
> On 09/03/15 13:07, Marcus Meissner wrote:
> > From d8df64a7261bc0febcdd48d4ed818dc1f36f3471 Mon Sep 17 00:00:00 2001
> > From: Marcus Meissner <meissner at suse.de>
> > Date: Thu, 3 Sep 2015 12:11:13 +0200
> > Subject: [PATCH] widl: implement a move-if-changed logic
> >
> > This avoids unnecessary rebuilds if the generated code by widl
> > does not change.
> 
> While I like the idea and it would often save a bug chunk of build time,
> I don't think it would work well with make. If you don't touch output
> file, then following make invocation will execute widl again, which is
> undesired.

I thought about this and it seems not easily solvable.

One dependency which could be avoided is tools/widl which due to config.h inclusion
is rebuilt on reconfigure. Of course this would be hoping that the output of widl
is stable.

So yeah, not really possible.

Ciao, Marcus