Currently a few potentially meaningful warnings are downgraded from error to warning even for NO_WARNING modules, git grep "Wno-error=" shows list. This list has grown a lot, mostly to quickly fix or hide some build issues when moving to a newer compiler.

One drawback is that these warnings now cause a lot of noise in the build output, potentially hiding new and relevant warnings.

I propose to discuss on these warnings to either

1. fix it in the code and remove the suppression, i.e. make it an error again for NO_WARNING modules
2. decide it's just not as important for us and suppress it completely, until a later review,