RFE: Document how to debug

[BrunoVernay]

It would be nice to have a HowToDebug.md or even a branch with debug information and flag set.

A branch could have the -DCMAKE_BUILD_TYPE=DEBUG instead of RELEASE for example. Or maybe just a documentation would be enough since, you would have to explain how to run

• flatpak run --devel --command=sh org.musescore.MuseScore
• gdb --args mscore -d (-d to get debug messages from Musescore https://musescore.org/en/handbook/3/command-line-options )

(Maybe it is possible to have -d by default ?)

Also having, this could help debuging Font issues

# Font issue debug  https://www.freedesktop.org/software/fontconfig/fontconfig-user.html#DEBUG  
#  Values: 16, 128, 1024 give reasonable output.  Value: 1, 2, 8, give huge output
- --env=FC_DEBUG=16

I could help to write things, and with the upcoming v7, it should be useful.

Also it would be super useful to explain how to write a patch. Currently, I cannot even find the source code, I guess it is removed after the build, but I am sure there is a Flatpak option to keep the source. Having the option ready in a "Debug branch" and a link to relevant flatpak documentation would be useful. (--keep-build-dirs in https://docs.flatpak.org/en/latest/flatpak-builder-command-reference.html ?)

[hfiguiere]

if you install org.musescore.MuseScore.Debug you should have the debug symbols

[hfiguiere]

Actually the build was missing the debug info. The next one should have them.

[BrunoVernay]

I started to work on https://github.com/BrunoVernay/org.musescore.MuseScore/blob/debug/README.md Feedback is welcome. Still too early for a pull request I think.