19.10 libomp-dev : Depends: libomp-9-dev (>= 9~) but it is not going to be installed

Have just upgraded from 19.04 to 19.10 and cannot seem to update libomp-dev:

$ sudo apt upgrade
Reading package lists... Done
Building dependency tree
Reading state information... Done
Calculating upgrade... Done
The following packages have been kept back:
  libomp-dev
0 to upgrade, 0 to newly install, 0 to remove and 1 not to upgrade.

$ sudo apt upgrade libomp-dev
Reading package lists... Done
Building dependency tree
Reading state information... Done
Calculating upgrade... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies.
 libomp-dev : Depends: libomp-9-dev (>= 9~) but it is not going to be installed
E: Broken packages

Have done an apt update too, without any complaints.