Don't depend on obsolete Guile features. (issue 109230043 by address@hidden)

[dak]

https://codereview.appspot.com/109230043/diff/1/lily/general-scheme.cc
File lily/general-scheme.cc (right):

https://codereview.appspot.com/109230043/diff/1/lily/general-scheme.cc#newcode269
lily/general-scheme.cc:269: protects are no longer needed in Guile 2.
What does "are no longer needed" mean?  What happens with the gc dumps
in lily.scm?  hashtable->alist is called on its result, and I get
Parsing...
guile> (hash-table->alist #f)
ERROR: In procedure hash-fold:
ERROR: Wrong type argument in position 3: #f
ABORT: (wrong-type-arg)

in the Scheme sandbox.  So this does not appear to do the right thing.

https://codereview.appspot.com/109230043/diff/1/lily/include/lily-guile.hh
File lily/include/lily-guile.hh (right):

https://codereview.appspot.com/109230043/diff/1/lily/include/lily-guile.hh#newcode124
lily/include/lily-guile.hh:124: return scm_append (scm_list_2 (x1, x2));
Good changes...

https://codereview.appspot.com/109230043/