fix the somehow newly introduced warnings

drivers/filter/md5.c

@@ -188,7 +188,7 @@ MD5Final (digest, ctx)
  * reflect the addition of 16 longwords of new data.  MD5Update blocks
  * the data and converts bytes into longwords for this routine.
  */
-static void
+void
 MD5Transform (buf, inraw)
      uint32 buf[4];
      const unsigned char inraw[64];

drivers/filter/optset.c

@@ -12,6 +12,7 @@
  *   May 2009 (D.C. van Moolenbroek)
  */
 
+#define _MINIX 1
 #include <stdlib.h>
 #include <string.h>
 #include <minix/config.h>

kernel/arch/i386/exception.c

@@ -152,10 +152,10 @@ PUBLIC void exception_handler(int is_nested, struct exception_frame * frame)
 	 * of a wrong pointer supplied by userland, handle it the only way we
 	 * can handle it ...
 	 */
-	  if (((void*)frame->eip >= copy_msg_to_user &&
-			  (void*)frame->eip <= __copy_msg_to_user_end) ||
-			  ((void*)frame->eip >= copy_msg_from_user &&
-			  (void*)frame->eip <= __copy_msg_from_user_end)) {
+	if (((void*)frame->eip >= (void*)copy_msg_to_user &&
+			(void*)frame->eip <= (void*)__copy_msg_to_user_end) ||
+			((void*)frame->eip >= (void*)copy_msg_from_user &&
+			(void*)frame->eip <= (void*)__copy_msg_from_user_end)) {
 		switch(frame->vector) {
 		/* these error are expected */
 		case PAGE_FAULT_VECTOR: