Let diff with golden test file ignore trailling cr

For compatibility with windows.

test/test-main.scm

@@ -19,12 +19,16 @@
   (call-with-input-file path
     (lambda (p) (read-string 65535 p))))
 
+(define (diff file1 file2)
+  (system (format #f "diff --strip-trailing-cr --color=auto -u ~a ~a" file1 file2)))
+
 (define* (golden-scene-test scene golden-file)
   (let ((output-file "bin/s7_scheme_tests.txt"))
     (call-with-output-file output-file
       (lambda (p) (write-string (godot scene) p)))
-    (unless (= 0 (system (format #f "diff --color=auto -u ~a ~a" golden-file output-file)))
-      (error 'assertion-error "ERROR: output of scene `~a` doesn't match golden file `~a`." scene golden-file))))
+    (unless (= 0 (diff golden-file output-file))
+      (error 'assertion-error
+             "ERROR: output of scene `~a` doesn't match golden file `~a`." scene golden-file))))
 
 (define (golden-scene-tests)
   (golden-scene-test