RSB --host and --target option trigger the bset tarball

[Chris Johns]

Deep in the set builder is an old piece of logic to trigger tarballs when in a cross-compile environment. This dates back to cross-compling tool sets.

The adding the kernel and 3rd party packages means the RSB command line can have the --host and --target options and if the kernel and a package like libbsd are on a single command line the --host and --target trigger a tarball install and this breaks the build.

Fix:

• Remove the tarball trigger.

• Check the kernel and packages are not effected. Having both may break a package build if passed automatically to a configure command line.

[Chris Johns <chrisj@…>]

In 9b1545f/rtems-source-builder:

sb/options: A Canadian Cross is a different host, build and target

The check must make sure each is different.

Closes #4017