64-bit fixes.
 [jmk] --rw-rw-r-- M 107020 glenda sys 2402 Nov 19 21:11 sys/man/6/snap
	/n/sourcesdump/2005/1119/plan9/sys/man/6/snap:18,24 - 
	/n/sourcesdump/2005/1120/plan9/sys/man/6/snap:18,24
	  check that this line begins with the specified prefix.
	  .PP
	  Throughout the rest of the snapshot, decimal strings are
	- always right-justified, blank-padded to 11 characters,
	+ always right-justified, blank-padded to at least 11 characters,
	  and followed by a single space character.
	  .PP
	  The rest of the snapshot is one or more records,