Fix syntax error in exit.c

This patch fixes a syntax error in exit.c that was introduced during the
ANSI-fication of newlib. The patch fixes a compile-time issue that arises when
newlib is configured with the --enable-lite-exit feature.

newlib/libc/stdlib/exit.c

@@ -54,7 +54,7 @@ exit (int code)
 {
 #ifdef _LITE_EXIT
   /* Refer to comments in __atexit.c for more details of lite exit.  */
-  void __call_exitprocs (int, void *)) __attribute__((weak);
+  void __call_exitprocs (int, void *) __attribute__((weak));
   if (__call_exitprocs)
 #endif
     __call_exitprocs (code, NULL);