[CMake] cmake for cygwin

[Marco Atzeri]

--- Mer 27/10/10, Bill Hoffman  ha scritto:

> On 10/26/2010 9:58 PM, Yaakov
> (Cygwin/X) wrote:
> > On Tue, 2010-10-26 at 17:53 -0400, Bill Hoffman
> wrote:
> >> Backwards compatibility may not be important to
> you, but to CMake it is
> >> very important.  When a developer chooses to
> use CMake, I want to
> >> respect that choice, and work as hard as I can to
> make sure I don't
> >> break that code.   CMake has been
> doing this for 10 years on cygwin,
> >> wrong or right that is how it has been
> done.   If there is code that
> >> builds with CMake on cygwin today, your suggested
> change will break that
> >> build.
> > 
> > No, it will most likely *fix* it.
> How is that possible?  If it is working today with the
> way CMake is for someone, and we make this change, it will
> stop working.  It can not *fix* something that is
> already working.  It can only break something that is
> already working, it can not fix something not broken...

Bill, it is not working. We don't succeed to port
programs using cmake as build chain in the cygwin distro,
using your package. I need to use Yaakov one.
So I need a working alternative.

I doubt any linux distribution will accept to release
a key tool that doesn't follow the distri guideline.

> > 
> > Bottom line: we insist that the CMake in the Cygwin
> distro not define
> > WIN32.  If you're prepared to handle that
> upstream now, great.  If not,
> > we will need to ship a patched version until this
> issue is rectified.
> > How do you wish to proceed?
> > 
> > 
> I guess you could release a patched cygwin that defaults to
> having the policy set to new, and I could release one that
> has the policy set to warn by default.
> 
> I suppose one other options is something like this:
> 
> "Warning: CMake has be forced to break backwards
> compatibility by the cygwin ports maintainers, we apologize
> if this broke your code. If your code does not compile, then
> set the cygwin policy to OLD, or add if(CYGWIN) set(WIN32 1)
> to your code."

I am not familiar with the cmake policy stuff. 
But it seems a workable solution.

> 
> We could emit that warning when cmake is run on cygwin for
> all projects until they require a new enough CMake that
> contains these changes by using the policy mechanism.
> 
> I would like to proceed by using the standard cmake policy
> mechanism. However, you have made it clear you will not be
> happy with that approach.
> 
> I am curious what you mean by "will need to ship a patched
> version until this issue is rectified."?  Will you
> block me from being the CMake maintainer for cygwin
> somehow?

This is something we would like to avoid, as the fallout 
will damage both the communities (cmake and cygwin).
Think of it as our last desperate solution (nuclear one).
 
> Sorry this is becoming so difficult.  I seriously just
> care about the existing CMake users and don't want to break
> things for them.
> 
> -Bill

Same for us. 
Cygwin users "usually" expect cygwin tools to 
build cygwin programs, not strange hybrid.

Marco