Enable compile warnings

This makes compile warnings non-fatal
4 jobs for pureos/byzantium in 11 minutes and 47 seconds (queued for 1 second)
Status Job ID Name Coverage
  Package
passed #328789
librem5
package:deb-debian-bullseye

00:02:24

passed #328790
librem5:arm64
package:deb-debian-bullseye:arm64

00:10:09

 
  Test Package
passed #328791
librem5
autopkgtest-debian-bullseye-package

00:01:38

passed #328792
librem5
lintian-debian-bullseye-package

00:00:39