Changes to *.env handling in master

[Joshua Root]

I've just pushed a mass update of 354 portfiles to maintain
compatibility with base on master. I tried to make the minimum necessary
changes to keep things working, and hopefully no behaviour changed. But
please keep an eye out in case I made a mistake.

The base change should fix the cases of mysteriously missing environment
variables that have occasionally cropped up. Unfortunately there was no
way to maintain complete backward compatibility while fixing the bugs,
but on the whole things should be much more consistent now.

The new rule is that one list element should contain one variable
assignment. Quote characters are no longer stripped out, so if you use
them anywhere that they're not meaningful to the Tcl parser, they will
end up in the final environment variable's value. (Previously it was
virtually impossible to put a literal quote character in an environment
variable because of the stripping.)

If you have any further questions about all this, please feel free to
ask me.

- Josh