It could well be that a workaround has already been proposed, but:

...

[74]
! Missing $ inserted.
<inserted text>  
               $
l.6592 ...re separated by an underscore: eg snake_
                                                 case)
?

Thoughts?

This was an interim glitch that has already been fixed here: https://sourceforge.net/p/gretl/git/ci/16a8f373e08c6d11c2f40d91c28b4e0fe2c487c0/

Please just update the source again (git pull).

cheers

sven