Trying to build on Mint 20 ...

Hi,

I'm trying to build Balsa on Mint 20. I'm currently stuck on configure  
telling me:

> checking whether to use an external spell checker... configure enchant
> checking for  enchant != 1.6.1 ... no
> configure: error: Package requirements ( enchant != 1.6.1 ) were not  
> met:
> 
> No package 'enchant' found

AFAICT I've got and enchant that is not 1.6.1:

> enchant is already the newest version (1.6.0-11.3build1).
> enchant-2 is already the newest version (2.2.8-1ubuntu0.20.04.1).

Any advice?

Many thanks,

Mike