tabs on otherwise empty lines

[William Lee Irwin III]

The <HELP> state is willing to consume config options as part of help
texts AFAICT:

(1)	[ \t]+  {
(2)	\n/[^ \t\n] {
(3)	[ \t]*\n        {
(4)	[^ \t\n].* {
(5)	<<EOF>> {

Now consider: "\tSome help text.\n\t\nconfig FOO\n\tdepends on BAR\n"

"\tSome help text." is consumed by (1).
"\n" is consumed by (3).
"\t\n" is consumed by (3) again.
"config FOO" is consumed by (4), which resets first_ts to last_ts,
	which does not actually change the value of first_ts.
"\tdepends on BAR\n" is consumed by (1), and does not zconf_endhelp()
	as the indentation level is the same as for "\tSome help text."

Better boundary detection logic is needed here.

Thanks,
Bill