[Groff] [Heirloom] Problem with specific TTF font

[Carsten Kunze]

Hello,

actually I don't think it is really a heirloom-doctools issue, but rather 
problem with the font or ghostscript.

The problem is described at

https://github.com/n-t-roff/heirloom-doctools/issues/33

With the test file supplied by the user and

troff -ms test.ps | dpost > test.ps
gs test.ps

I get the same errors. When I use other TTF fonts it works.

The first error line from ghostscript is

Error: /typecheck in --readonly--

When I compare test.ps proccessed with this an a other font the first different 
line with the not working font is

/Notice (APL385) readonly def

Could this be a hint to the cause?

Thanks,
Carsten