Changed Framework icon promises to use delay/sync instead of delay. This

appears to prevent a bug whereby multiple threads attempt to force one of the
promises at the same time, causing the promise to believe it is being used
recursively.  All Framework tests passed (on OS X) after making this change, not
that I really expect the icons to be particularly crucial to the tests.

svn: r16820

collects/framework/private/icon.ss

@@ -30,25 +30,25 @@
   (import mred^)
   (export framework:icon^)
   
-  (define eof-bitmap (delay (let ([bm (make-object bitmap% eof-bitmap-path)])
+  (define eof-bitmap (delay/sync (let ([bm (make-object bitmap% eof-bitmap-path)])
                               (unless (send bm ok?)
                                 (error 'eof-bitmap "not ok ~s\n" eof-bitmap-path))
                               bm)))
   (define (get-eof-bitmap) (force eof-bitmap))
   
-  (define anchor-bitmap (delay (make-object bitmap% anchor-bitmap-path)))
+  (define anchor-bitmap (delay/sync (make-object bitmap% anchor-bitmap-path)))
   (define (get-anchor-bitmap) (force anchor-bitmap))
   
-  (define lock-bitmap (delay (make-object bitmap% lock-bitmap-path)))
+  (define lock-bitmap (delay/sync (make-object bitmap% lock-bitmap-path)))
   (define (get-lock-bitmap) (force lock-bitmap))
   
-  (define unlock-bitmap (delay (make-object bitmap% unlock-bitmap-path)))
+  (define unlock-bitmap (delay/sync (make-object bitmap% unlock-bitmap-path)))
   (define (get-unlock-bitmap) (force unlock-bitmap))
   
-  (define autowrap-bitmap (delay (make-object bitmap% return-bitmap-path)))
+  (define autowrap-bitmap (delay/sync (make-object bitmap% return-bitmap-path)))
   (define (get-autowrap-bitmap) (force autowrap-bitmap))
   
-  (define paren-highlight-bitmap (delay (make-object bitmap% paren-bitmap-path)))
+  (define paren-highlight-bitmap (delay/sync (make-object bitmap% paren-bitmap-path)))
   (define (get-paren-highlight-bitmap) (force paren-highlight-bitmap))
   
   (define-syntax (make-get-cursor stx)
@@ -57,7 +57,7 @@
        (syntax
         (begin
           (define id 
-            (let ([ans (delay 
+            (let ([ans (delay/sync 
                          (let* ([msk-b (make-object bitmap% mask-path)]
                                 [csr-b (make-object bitmap% csr-path)])
                            (if (and (send msk-b ok?)
@@ -72,8 +72,8 @@
   (make-get-cursor get-up/down-cursor up-down-mask-path up-down-csr-path 'size-n/s)
   (make-get-cursor get-left/right-cursor left-right-mask-path left-right-csr-path 'size-e/w)
   
-  (define mrf-on-bitmap (delay (make-object bitmap% mrf-bitmap-path)))
+  (define mrf-on-bitmap (delay/sync (make-object bitmap% mrf-bitmap-path)))
-  (define gc-on-bitmap (delay (make-object bitmap% gc-on-bitmap-path)))
+  (define gc-on-bitmap (delay/sync (make-object bitmap% gc-on-bitmap-path)))
   
   (define (make-off-bitmap onb)
     (let* ([bitmap (make-object bitmap%
@@ -84,8 +84,8 @@
       (send bdc set-bitmap #f)
       bitmap))
   
-  (define mrf-off-bitmap (delay (make-off-bitmap (force mrf-on-bitmap))))
+  (define mrf-off-bitmap (delay/sync (make-off-bitmap (force mrf-on-bitmap))))
-  (define gc-off-bitmap (delay (make-off-bitmap (force gc-on-bitmap))))
+  (define gc-off-bitmap (delay/sync (make-off-bitmap (force gc-on-bitmap))))
   
   (define (get-gc-on-bitmap)
     (force