For the record:
Please ignore my last comment. Not the case.
I found that AppVeyor nowadays does have complete recent versions of MinGW pre-installed on the builder VMs (used to not be the case).
Switching to those made the builds successful (and simpler and faster).
For the record:
Please ignore my last comment. Not the case.
I found that AppVeyor nowadays does have complete recent versions of MinGW pre-installed on the builder VMs (used to not be the case).
Switching to those made the builds successful (and simpler and faster).