Typo in strtol(3).

Noticed by:	bde
Simplify pause_sbt() logic. Don't call DELAY() if remainder is less
than or equal to zero.
sh: Cast -1 to pointer rather than pointer to variable of wrong type.

NEOF needs to be a non-null pointer distinct from valid union node pointers.
It is not dereferenced.

The new NEOF is much like SIG_ERR except that it is an object pointer
instead of a function pointer.

The variable tokpushback can now be static.
The round of expand_number() cleanups.
o Fix range error checking to detect overflow when uint64_t < uintmax_t.
o Remove a non-functional check for no valid digits as pointed out by Bruce.
o Remove a rather pointless comment describing what the function does.
o Clean up a bunch of style bugs.

Brucified by:	bde
sh: Recognize "--" as end of options in type builtin.

This implementation makes minimal changes: command names starting with "-"
(other than "--") can still be queried normally.
sh: Add a function for the case where one token is required in the parse.