VCL_STRANDS

[Poul-Henning Kamp]

I have gone over the VCC and added an alternate way of passing
a uncomposed string to functions, as an alternative to STRING_LIST.

STRANDS is basically a STRING_LIST which gets stuffed into a
on-stack struct, so that more than one STRANDS argument can be
passed to a (VMOD-)function, something which is not possible
with STRING_LIST because it uses the var-args mechanism.

One place where this is now used is in string comparisons in
VCL, this may save significant workspace for some users.

While at it, I have also added support for <, <=, >= and > 
string comparisons.

In the process I have done major surgery on string-handling
in VCC, cleaning it up in the process, and therefore I kindly
ask everybody to be on the lookout for things which changed or
fails now.

Feedback from VMOD writers welcome...

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
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FreeBSD committer       | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.