expander: fix reader bug

Fix incorrect comparison of character to EOF. There's a test, already,
but the test fails only if the expander is compiled in safe mode.

pkgs/racket-test-core/tests/racket/read.rktl

@@ -1122,7 +1122,8 @@
 		 (parameterize ([print-unreadable #f])
 		   (display x p)))
 	   (err/rt-test (parameterize ([print-unreadable #f])
-			  (write x p))))]
+			  (write x p))
+                        exn:fail?))]
 	[try-good
 	 (lambda (x)
 	   (test (void) (list x)

racket/src/cs/Makefile

@@ -5,7 +5,7 @@ RACKET = ../../bin/racket
 SCHEME = scheme
 
 # Controls whether Racket layers are built as unsafe:
-UNSAFE_COMP = # --unsafe
+UNSAFE_COMP = --unsafe
 
 # Controls whether compiled code is compressed:
 COMPRESS_COMP = # --compress

racket/src/expander/read/extension.rkt

@@ -43,7 +43,7 @@
                                             in
                                             config))
   (define c (read-char/special in config))
-  (unless (char=? c #\space)
+  (unless (eqv? c #\space)
     (reader-error in config
                   "expected a single space after `~a`"
                   extend-str))
@@ -56,7 +56,7 @@
 (define (read-extension-#! read-recur dispatch-c in config
                            #:get-info? [get-info? #f])
   (define c (read-char/special in config))
-  (unless (char-lang-nonsep? c)
+  (unless (and (char? c) (char-lang-nonsep? c))
     (bad-syntax-error in config (if (char? c)
                                     (string dispatch-c #\! c)
                                     (string dispatch-c #\!))))