Why not use an invisible grace note to start the glissando? Then,
there's no need to fiddle with the timing:
\transpose c c'{
\grace{ \hideNotes g,8\glissando \unHideNotes} c'4 c'4 c'4 r4 |
\grace{\hideNotes c''8\glissando \unHideNotes} c'4 c'4 c'4 r4 |
a1\fermata \grace{\hideNotes d'4\glissando \unHideNotes }|
ees8->[ c8]-> r4 r2 |
}
Well, to answer my own question, the hidden grace note will be so
close to the following note, that the resulting glissando might
look too short. One possible workaround is to include more hidden
notes (or spacer notes) in the \grace{...}:
\grace{ \hideNotes g,8\glissando s s \unHideNotes} c'4 c'4 c'4 r4
|