build: Show debug and optimisation flags in summary

These can be confusing as Meson provides `--buildtype=`, `-Ddebug=`
and `-Doptimization=` which can override each other.
4 jobs for sam/show-debug in 6 minutes and 6 seconds (queued for 1 second)
latest
Status Job ID Name Coverage
  Test
passed #1005233
test-alpine-edge

00:01:39

passed #1005234
test-fedora-latest

00:01:38

passed #1005235
test-ubuntu-rolling

00:01:35

 
  Analysis
passed #1005236
coverage-analysis

00:04:26

76.0%