If the `dep` is a two char string (as "qt"), the `platform, name = dep`
will split the string and search for 't' dependency in 'q' platform.
So, we have to be sure that the dep is a tuple before splitting it.
By building kiwix-android on the `android` platform, we can now build
`kiwix-lib` on all `android_<arch>` platforms, and so have all
architectures in the same apk.
Fix#108
A metaplatform allow to regroup sereval platform together.
When a target is added to the platform, the target is dispatched/add to
all sub platforms.
As the step (metaplatformName, target) is not really added, we have to
track which steps are really added, so `add_targets` need to return the
list of added targets.
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.
Introduce also a "NeutralEnv", a build environment independent of the
targeted platform. All `Source` now build using the neutralEnv.
Most of toolchains are also using neutralEnv except android_ndk who is
specific to a platform.
As toolchain are neutral, platform specific environment variables are now
set by the platformInfo directly instead of the toolchain.
