parser-ly-from-scheme: Make #{ compilable (issue 581610043 by address@hidden)

[thomasmorley65]

Afaict, LGTM

A remark:


https://codereview.appspot.com/581610043/diff/569310043/scm/parser-ly-from-scheme.scm
File scm/parser-ly-from-scheme.scm (right):

https://codereview.appspot.com/581610043/diff/569310043/scm/parser-ly-from-scheme.scm#newcode19
scm/parser-ly-from-scheme.scm:19: (define (read-lily-expression-internal
lily-string filename line closures)
I was going to write that we would need to care about displayLilyMusic
as well, though checking again I noticed:

\void \displayLilyMusic 
\new Voice { \applyContext #(lambda (ctx) (display ctx)) b4 }

with an older lily-build against guile-2.0.14 returns:

\new Voice { \applyContext ##f
 b4 }

A todays build with guile-2.2.6 returned:

\new Voice { \applyContext #(lambda (ctx) (display ctx))
 b4 }

Which is nice.

Not sure whether it's a lilypond or guile improvement.

https://codereview.appspot.com/581610043/