Fix issues with Windows and macOS

[amyspark]

👋

This PR should take care of loading dylibs on macOS, linking against substrate's logger class on macOS (crunchMake needs further work here re: loader_path), and working around Meson interpreting declare_dependency variables under the hood.

[codecov]

Codecov Report

Patch coverage has no change and project coverage change: -13.48% ⚠️

Comparison is base (9147009) 82.25% compared to head (538d06d) 68.76%.

Additional details and impacted files

@@             Coverage Diff             @@
##             main      #28       +/-   ##
===========================================
- Coverage   82.25%   68.76%   -13.48%     
===========================================
  Files          21       17        -4     
  Lines        1746     1495      -251     
  Branches      517      437       -80     
===========================================
- Hits         1436     1028      -408     
+ Misses        278      244       -34     
- Partials       32      223      +191     

Files Changed	Coverage Δ
crunch++/crunch++.cpp	32.34% <ø> (-15.21%)	⬇️
crunch/crunch.c	69.33% <ø> (-13.26%)	⬇️

... and 18 files with indirect coverage changes

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[dragonmux]

This all LGTM, we'll check that the tests are running in CI on one of the "working" runs and merge. Thank you very much for the contribution!