Fix some warnings (gint formatting, size_t/int mix, etc)

[bynect]

Related to #1372

[codecov-commenter]

⚠️ Please install the to ensure uploads and comments are reliably processed by Codecov.

Codecov Report

Attention: Patch coverage is 85.36585% with 18 lines in your changes missing coverage. Please review.

Project coverage is 65.21%. Comparing base (63e6e88) to head (c3e648b).
Report is 2 commits behind head on master.

Files with missing lines	Patch %	Lines
src/notification.c	0.00%	8 Missing ⚠️
src/rules.c	0.00%	3 Missing ⚠️
src/menu.c	0.00%	2 Missing ⚠️
src/dunst.c	0.00%	1 Missing ⚠️
src/queues.c	93.75%	1 Missing ⚠️
src/settings.c	0.00%	1 Missing ⚠️
src/wayland/wl.c	0.00%	1 Missing ⚠️
src/x11/screen.c	0.00%	1 Missing ⚠️

❗ Your organization needs to install the Codecov GitHub app to enable full functionality.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1424      +/-   ##
==========================================
+ Coverage   65.17%   65.21%   +0.04%     
==========================================
  Files          50       50              
  Lines        8723     8737      +14     
  Branches     1034     1034              
==========================================
+ Hits         5685     5698      +13     
- Misses       3038     3039       +1     

Flag	Coverage Δ
unittests	65.21% <85.36%> (+0.04%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

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

[bynect]

@fwsmit I replaced this g_free with an actual function taking two arguments since it just seemed wrong. Was this supposed to free both the pixels and data_pb?

[bynect]

Int formatting was a problem on Openbsd and on x86 architecture. I tried to fix some other warnings like unused param and size_t instead of int