qt5-qtwebengine : add webengine-proprietary-codecs option

[kaamui]

Without this option, the webengine is unable to read videos on some major platforms like Vimeo, PeerTube, even some HTML5 videos like on this page : ​https://www.w3schools.com/html/html5_video.asp

The option is always turned ON on linux distros, even in Debian. I built qtwebengine myself and didn't see any dependency related to this option that could explain what it is not currently enabled via the port.

I tried to edit the portfile to submit a pull request but I'm facing a non-related issue with the SDK ("could not resolve sdk macosx12.3" where I only have macosx13.1 SDK), but I can't see why it would be more complicated to do via MacPort than it was by myseld :

sudo port install bison
sudo port install flex
sudo port install nodejs12
sudo port install ninja

python3 -m pip install html5lib

git clone https://code.qt.io/cgit/qt/qtwebengine.git
cd qtwebengine
git checkout 6.4.2
git submodule update --init --progress
mkdir build
cd build
qt-configure-module .. -webengine-proprietary-codecs -- -DCMAKE_OSX_ARCHITECTURES="x86_64;arm64"
cmake --build . --parallel
sudo cmake --install .

Note that the same is possible using Qt 5.15, that is based on qmake instead of cmake (tested on Linux, but as I already said, could not confirm it on OSX as I'm stuck by this SDK issue) :

qmake .. -- -proprietary-codecs

On a side note, being new to MacPorts, I read the doc but could not find a direct answer on how to simply rebuild a port where you just modified the Portfile. I tested to edit it and to run sudo port build qt5-qtwebengine. Is it the right way to do so ?