Supply definitions for __COPYRIGHT and __RCSID if the system lacks them.

Avoid conflicting definitions for MAX()

Note that there still appears to be a missing definition, something
is being implicitly declared:
    dd.c: In function ‘f_count’:
    dd.c:1234: warning: large integer implicitly truncated to unsigned type
    dd.c: In function ‘f_seek’:
    dd.c:1282: warning: large integer implicitly truncated to unsigned type
    dd.c: In function ‘f_skip’:
    dd.c:1289: warning: large integer implicitly truncated to unsigned type
diff --git a/dd.c b/dd.c
index c6af3ea..5dbcf9a 100644
--- a/dd.c
+++ b/dd.c
@@ -34,11 +34,20 @@
  */
 
 #include <sys/cdefs.h>
+
+#ifndef __COPYRIGHT
+#define __COPYRIGHT(x)
+#endif
+
 #ifndef lint
 __COPYRIGHT("@(#) Copyright (c) 1991, 1993, 1994\n\
 	The Regents of the University of California.  All rights reserved.\n");
 #endif /* not lint */
 
+#ifndef __RCSID
+#define __RCSID(x)
+#endif
+
 #ifndef lint
 #if 0
 static char sccsid[] = "@(#)dd.c	8.5 (Berkeley) 4/2/94";
@@ -61,6 +70,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
+#include <stdint.h>
 
 #include "dd.h"
 
@@ -97,6 +107,9 @@
 extern u_char		casetab[];
 
 
+#ifdef MAX
+#undef MAX
+#endif
 #define MAX(a, b) ((a) > (b) ? (a) : (b))
 
 static void dd_close(void);
@@ -1354,5 +1367,3 @@
 }
 
 #endif	/* NO_CONV */
-
-