Debugging

To properly debug a segfault we need to use a build with libtorrent and qBittorrent debug symbols included.

Some reasons I don’t release them here:

static builds using b2 the libtorrent debug symbols can add 100MB to the file size.
static builds using cmake are about 15MB larger and potentially slower.
It doubles the build time.
It’s not needed for most users.

The easiest way to get a debug build is to build it yourself by

forking the repo the repo and running the ci-main-reusable-caller.yml workflow with the debug flag enabled.

The builds will be uploaded as artifacts to the workflow run and can be downloaded from there.
Build it yourself locally

This can be done one of two ways with the recommended method being the second, for general purpose debugging.
- First, Full debug mode binary.
  
  All apps have debug mode set to true where applicable.
  
  This can be done when building locally by using the -d flag or export qbt_build_debug=yes
- Second, Release binary with debug symbols
  
  By not stripping the binary, this allows you to have a binary with release binary with debug symbols.
  
  This sets the below flags which does not optimise any debug sections but apps are not set to debug mode.
```
# defaults if both are set to no
qbt_strip_qmake='-nostrip'
qbt_strip_flags=''
qbt_optimise_gcc="-Og -g" # https://gcc.gnu.org/onlinedocs/gcc/Optimize-Options.html#index-Og
qbt_optimise_linker="-Wl,-O0"
```
  This can be activated by using these flags:
```
export qbt_build_debug=no # a default option
export qbt_optimise_strip=no # When not stripped the Binary is optimised with -Og
export qbt_use_lto=no # Native Alpine host only setting. LTO is not used in cross builds
```

A custom version of qbt-mcm can be set using these flags:

# testing = easy way to switch to test qbt-musl-cross-make-test builds via an env in the workflow.
qbt_mcm_url="userdocs/qbt-musl-cross-make" # the default setting
# provide the github tag and it will use that to download instead of the latest release.
export qbt_mcm_tag="2614"

Then you will have a debug build with the debug symbols included to get stack traces using gdb.