Fedora and Cross Compiling

[Andy Green]

Brendan Conoboy wrote:
> Andy Green wrote:
>> I would be the first to reach for a dirty but unanswerably effective
>> hack to get me where I am going...  But in this case I think the only
>> true answer is to tag BuildRequires as being host or target in the spec
>> file, not to unmanageably duplicate the target-world dependencies in the
>> host.  Eg
>>
>> HostBuildRequires: byacc  (<-- for it is he)
>> BuildRequires: libblah-devel
>>
>> ...where they are considered the same deal when hostArch == buildArch.
> 
> Or TargetBuildRequires.  Either way it's invasive and should be avoided
> if it can be worked around.  You really want the build system to do as
> much as it can so you don't impact package maintainers unless absolutely
> necessary.

Yep, it is invasive but it is also defensible I think.  It's the kind of
thing that could be patched into the specfile at buildtime per-arch if
that is what ends up happening.

But here's an alternative Heuristic that isn't as reliable but might
cope and has no specfile footprint

 1) Package is called lib* or *-devel?  goto 8

 2) Check build host rpmdb

 3) If present, check if any of the files in the package match
/usr/lib/*.so or /usr/lib/*.a or /usr/include/*... if not, consider it
present, else...

 4) Check target arch rpmdb

 5) If absent, goto 7

 6) check if any of the files in the package match /usr/lib/*.so or
/usr/lib/*.a or /usr/include/*... if so, consider it present, else...

 7) error out with "package not installed on build host" (it didn't have
a footprint in /usr/lib or /usr/include, take as a host utility)

 8) Check target arch rpmdb

 9) if absent, error out with "package not installed for $arch"

10) consider it present

-Andy

>> We can see if this logic raises objections anywhere given the effective
>> forkage of rpm but I suspect it is a basic fact necessary for cross to
>> work in rpm semantics.
> 
> Forkage?

There's rpm5.org and there's rpm.org trees now.  If it was the plan to
add a new spec keyword, one would want it to be globally accepted and
not become one tree's special sauce.

-Andy