[Buildroot] Two stages compilation

[Thomas Petazzoni <thomas.petazzoni@free-electrons.com>]

Thomas, Angelo,

On Wed, 30 Apr 2014 20:44:57 +0200, Thomas De Schampheleire wrote:

> >> A couple of months back i was able to package mono for OpenWrt (which is
> >> in this sense close to Buildroot), but i haven't finalized that project
> >> (as it turned out that the target MIPS CPU is not totally supported by
> >> Mono...). If you think it's useful, i can dig this out from the archive
> >> and share the package definition with you. Please let me know if so.
> 
> Note that Alexander Varnin has submitted a patch to the list for the
> mono runtime a while back:
> http://patchwork.ozlabs.org/patch/299488/

Though this particular package only provides a target version of Mono,
which probably means that it relies on mono being installed on the
build machine to be able to build all the Mono C# libraries (i.e step 2
in Angelo's description).

So indeed, as Zoltan pointed out, most likely the solution is to have
both a target and a host variant for Mono. The host variant builds the
compiler, and is used on the build machine to compile all the Mono C#
libraries into the corresponding byte code. The target variant builds
the "virtual machine" that runs on the target. And obviously most
likely the target variant will have a dependency on the host variant.

Also, the host variant building the compiler will be useful if people
want to package other Mono libraries/applications.

Thomas
-- 
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com