-L option in tar 1.13

[BStrand7]

Greetings,

I think I've found a compare sense issue in the parsing of the parameter for 
the -L (tape length) option.  The parameter is parsed on line 657 of tar.c 
using xstrtoul, as follows:

if (xstrtoul (optarg, (char **) 0, 10, &u, "") != LONG_MAX)
  USAGE_ERROR ((0, 0, _("Invalid tape length")));

Looking at ../lib/xtrtol.c, it appears that LONG_MAX is returned in the case of 
an overflow.  In order for a valid length parameter to pass the above test, 
therefore, the sense must be reversed, as in "if... == LONG_MAX".  I've made 
this change, rebuilt, and the program now appears to work as expected, so I 
thought I'd run it by you folks.  Please let me know if you see any other 
ramifications of running like this that I'm not seeing, as I'm planning to put 
the patched version in a production environment.

Regards,
Brian Strand