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
1 file changed