Figured bass: extender line without a number

[Jun Tamura]

Hello,

I’m trying to typeset J. S. Bach’s Orchestral Suite No. 2 and come across the 
attached figured bass. Is there a good way to achieve this in LilyPond? Bach 
often uses a short horizontal line, like a minus sign, instead of “3” to 
indicate the third. I can typeset that with:
< \markup “-“ >
but I cannot find a way to draw an extender line without a number at the 
beginning.

Thanks in advance for your help.

Jun