Revert "refine define"

This reverts commit 328f38a128.

define.rkt

@@ -1,24 +1,8 @@
 #lang racket/base
 (require (for-syntax racket/base))
+(require racket/contract)
 
-(provide (all-defined-out))
-
-;; this macro requires that the source file also contain
-;; (module+ safe
-;;  (require racket/contract))
-
-(define-syntax (define+provide+safe stx)
-  (syntax-case stx ()
-    [(_ (proc arg ... . rest-arg) contract body ...)
-     #'(define+provide+safe proc contract
-         (λ(arg ... . rest-arg) body ...))]
-    [(_ name contract body ...)
-     #'(begin
-         (define name body ...)
-         (provide name)
-         (module+ safe 
-           (require racket/contract)
-           (provide (contract-out [name contract]))))]))
+(provide define+provide define+provide/contract define/contract+provide)
 
 ;; each define macro recursively converts any form of define
 ;; into its lambda form (define name body ...) and then operates on that.