Sync dev with stable

[jagerman]

In merging dev into stable, I was left with a few small differences for small changes/fixes that are present on stable but not dev.

Nothing major here:

• Explicitly set OFF in CI jobs if werror is false.
• Fix ci comment about stable build
• Add missing bcrypt system linkage for windows static build
• make sure oxenc headers are available via common
• add missing boost header for version check to boost variant wrapper
• drop unused patch (this used to be used in mingw static builds, but was applied upstream quite a while ago, and was dropped from stable but apparently only the application, but not the patch itself, got dropped from dev).