Adapt comphelper::ThreadPool to Emscripten's threading needs

...by keeping the worker threads around by default instead of joining and later
re-spawning them; see 5b1df7709d75c6dd993da5a272e7e37e55a70174 "Document the
Emscripten threads issue".  But lets be cautious and change the bJoin default
only for Emscripten.

Also, cap the thread pool size to MAX_CONCURRENCY=4 and increase to
-sPTHREAD_POOL_SIZE=6.  In an experimental setup where the Emscripten build
starts up with the start center rather than a Writer document, that is just
enough to cover the thread-spawning needs when executing the start center
window's paint task:  Four threads for the comphelper::ThreadPool (used from
within drawinglayer::convertToBitmapEx -> ... ->
BitmapBasicMorphologyFilter::filter), and one each for
configmgr::Components::WriteThread (see e8358d0a0f7c2c4b1ccf800fe9ec8a7f2bf7066a
"Keep around a single configmgr::Components::WriteThread instance") and
salhelper::TimerManager.

Change-Id: I5b1d0e9dc09f05fb3b679c8dc1c38ee45c61c0f8
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/171004
Reviewed-by: Stephan Bergmann <stephan.bergmann@allotropia.de>
Tested-by: Jenkins

0 files changed, 0 insertions, 0 deletions