Instead of having the run_command function setting the
env from the buildEnv, this is the dependency that create the
env and then pass it to the run_command function.
This way, each dependency will be able to set a specific env.
This is needed for win32 on fedora.
It is better to use a specific pkg-config than setting a PKG_CONFIG_LIBDIR.
This avoid other CI (libzim/...) to set a env var specific to win32 build.
This is the big change !!!!
Instead of handling target as primary object and prepare/build targets,
we are handling build steps.
A build step may be a source (preparation) or a build (of the source).
Actualy, a step is a tuple (context, Builder or Source).
The context define the context of the step. It can be :
- 'source', for a Source step
- 'neutral' or the name of a platform for Build step.
Target becomes a "Class only" class.
Sometime the root_path is dependent of the target platform and sometime
not. But sometime dependent of the build arch :/
[TODO] We should move the cross_file generation to the PlatformInfo class.