AppVeyor may update minor version of Qt and change `5.11.0` to `5.11.1`.
If we use the path with the full version, it will break in the futur.
AppVeyor install a link `5.11` pointing to the last version, so let's use
it.
We never use the android platform in other project. We always an arch
specific android platform (android_arm).
So, do not try to do any dependencies archives there.
Especially if travis kill the job because it takes too long to create
the archive.
As we now move to multi-arch build, we may have things compiled natively
or "neutral" (as toolchains). So we cannot use the BASE_DIR as
relative_path because BASE_DIR is arch dependent.
Compiling all dependencies for all archs takes a too long time for travis.
By downloading the cache of specific android arch, we avoid to recompile
them.
Android will need kiwix-lib builder to build, so we cannot make the
target_only.
If we are building a PR comming from a fork, the secret key will not
be available and we cannot decrypt the ssh key.
And if the ssh key cannot be decrypted, we should not try to use it to
upload base dependencies.
`cron` and deployement are made only on "secured environment" so we don't
need to test for existance of the key because we are sure that we have
been able to decrypt it.
`travis/compile_all.py` may need the secret key to upload dependencies
cache to our server.
So, just decrypt the key before the upload is not good enough (and breaks
PR building new version of base dependencies)
This reverts commit 74efad49e2.
Is a contributor do a PR from its own repository, we will try do decrypt
the key but fail because secret env var are not available.
We need the secret key only if we do a deployement and the deployement is
done only for a tag or a cron job.
SVN checkout can be pretty long to do (especially if icu serveur is pretty
slow).
By downloading an archive on our own server, we avoid a spending too many
time downloading.
The archive is a simple targz of the SVN checkout.
The deps will be build only if we are in a cron.
In this case, we can directly build only the target.
But in other case, we have to build the target and its dependencies.
