[9fans] atol() bug

[Bakul Shah]

The atol() manpage says:

          Atoi and atol recognize an optional string of tabs and
          spaces, then an optional sign, then a string of decimal dig-
          its.

And yet atol(x) acts exactly like strol(x, nil, 0). This makes
it unnecessarily incompatible with the unix version.  Ditto
for atoll(). My preference would be to fix the code and not
the man page.