This commit enables building with upstream CMake PCH support.
Change-Id: Ib37745b00e7560e804483e7c2c2a3fa7cf6d663c
Reviewed-by: Eike Ziller <eike.ziller@qt.io>
add_qtc_plugin now takes a flag "INTERNAL_ONLY". These internal plugins
will not show up in the project configuration nor in the feature summary.
This flag is used by the tests that build plugins.
Change-Id: I1912dd62221b2624ed7326df381fbbceccefbdac
Reviewed-by: Eike Ziller <eike.ziller@qt.io>