Staves with StaffSymbol #'line-count = #1 produce "not a number" warnings and wrongly cropped images

[Reinhold Kainhofer]

The attached minimal example sets the staff's StaffSymbol #'line-count = #1
which causes several NaN warnings. Furthermore, the preview image is cropped 
way too much (apparently only the staff lines and the note heads are taken 
into account for the height of the image).

Error output is:

address@hidden:~/lilypond/lilypond$ LANG=C lilypond -dpreview staff-one-
line-NaN.ly 
GNU LilyPond 2.15.12
Processing `staff-one-line-NaN.ly'
Parsing...
Interpreting music... 
Preprocessing graphical objects...
Finding the ideal number of pages...
Fitting music on 1 page...
Drawing systems...
programming error: insane spring min_distance requested, ignoring it
continuing, cross fingers
programming error: Infinity or NaN encountered
continuing, cross fingers
Layout output to `staff-one-line-NaN.ps'...
warning: Found infinity or nan in output. Substituting 0.0
warning: Found infinity or nan in output. Substituting 0.0
Converting to `./staff-one-line-NaN.pdf'...
Layout output to `staff-one-line-NaN.preview.eps'...
warning: Found infinity or nan in output. Substituting 0.0
warning: Found infinity or nan in output. Substituting 0.0
Converting to `./staff-one-line-NaN.preview.pdf'...
Converting to PNG...
Success: compilation successfully completed


cheers,
Reinhold
-- 
------------------------------------------------------------------
Reinhold Kainhofer, address@hidden, http://reinhold.kainhofer.com/
 * Financial & Actuarial Math., Vienna Univ. of Technology, Austria
 * http://www.fam.tuwien.ac.at/, DVR: 0005886
 * LilyPond, Music typesetting, http://www.lilypond.org

staff-one-line-NaN.ly
Description: Text Data

staff-one-line-NaN.pdf
Description: Adobe PDF document

staff-one-line-NaN.preview.png
Description: PNG image