Merge branch 'master' into nested-bookparts

Conflicts:

	scm/midi.scm

diff --cc scm/midi.scm
index 863128e905fd6a6ce37634e32a4d2c5d5393247f,5d3277d820095e2c4deca9cd5ebc76bbd53c83a3..cf43d3af7592759e5f5887812a1b6f2667665ce1
--- 1/scm/midi.scm
--- 2/scm/midi.scm
+++ b/scm/midi.scm
@@@ -284,18 -284,19 +284,17 @@@ returns the program of the instrumen
  ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  ;;
  
 -(define-public (write-performances-midis performances basename)
 +(define-public (write-performances-midis performances basename . rest)
+   (let ((midi-ext (ly:get-option 'midi-extension)))
 -    (let
 -      loop
 -      ((perfs performances)
 -       (count 0))
 -
 -
 -      (if (pair?  perfs)
 -        (begin
 -          (ly:performance-write
 -           (car perfs)
 -           (if (> count 0)
 -               (format #f "~a-~a.~a" basename count midi-ext)
 -               (format #f "~a.~a" basename midi-ext)))
 -          (loop (cdr perfs) (1+ count)))))))
 +  (let
 +      loop
 +    ((perfs performances)
 +     (count (if (null? rest) 0 (car rest))))
- 
- 
 +    (if (pair?  perfs)
 +      (begin
 +        (ly:performance-write
 +         (car perfs)
 +         (if (> count 0)
-              (format #f "~a-~a.midi" basename count)
-              (format #f "~a.midi" basename)))
++             (format #f "~a-~a.~a" basename count midi-ext)
++             (format #f "~a.~a" basename midi-ext)))
 +        (loop (cdr perfs) (1+ count))))))