add license to package info.rkt file

related to racket/racket#3760
related to spdx/license-list-XML#1346

LICENSE

@@ -9,6 +9,7 @@ and
   https://github.com/racket/racket/blob/master/racket/src/LICENSE-MIT.txt
 for the full text of the licenses.
 
-This repository incorporates code from Tiny CLOS which is copyright
-Xerox. See the file tiny-clos.rkt for the license, which is similar to
-the MIT License.
+This repository incorporates code from Tiny CLOS, which is copyright
+Xerox and released under a variant of the Xerox License. See the file
+tiny-clos.rkt for the full text of the license, which is similar to
+the MIT License.

info.rkt

@@ -46,3 +46,9 @@
 (define pkg-desc "The implementation of the Swindle language")
 
 (define pkg-authors '(eli))
+
+(define license
+  ;; TODO: Update this if https://github.com/spdx/license-list-XML/pull/1346
+  ;; concludes that the Tiny CLOS license should be assigned a different
+  ;; license rather than Xerox.
+  '(Xerox AND (Apache-2.0 OR MIT)))