This can be used to configure extra cmake args for the documentation
build in coin.
Change-Id: I11417bee9630aebe0bbc118cd843b1536101da71
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>
(cherry picked from commit b956a909c5ff29bf9824c054750966bdec42c6ca)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>