coin: Add instructions to generate docs during testing

A single configuration provides qdoc and qtattributionsscanner via
provisioning. The environment variables instruct QDoc to run in
testing mode; it ignores linking warnings (since we don't have .index
files for external documentation modules) and terminates with non-zero
exit code if documentation warnings exceed the limit set in the
documentation config.

The provisioned binaries are portable, packaged together with their
dependencies. As they are installed under /opt, the instructions
create symlinks to the binaries in the install directory before
building the 'generate_docs' target.

Task-number: QTBUG-78069
Fixes: QTBUG-95554
Change-Id: I4a4765250247e2fc6eddd153c36cf8126ddd10ae
Reviewed-by: Paul Wicking <paul.wicking@qt.io>
(cherry picked from commit 439f6c9576f33df4495364f2534551c98d9c47d7)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

0 files changed, 0 insertions, 0 deletions