[PATCH modular 03/13] build.sh: allow user to specify an alternate bin directory

[Trevor Woerner]

For this entire patch series I still can't understand why we need to
define an explicit _SET variable which defines whether or not the base
variable is defined, or not.

For every one of the new variables you have defined you have included
the following:

> +# States if the user has exported BINDIR
> +if [ X"$BINDIR" != X ]; then
> +    BINDIR_SET=yes
> +fi

And then you subsequently check to see if (using the specific
variables for this specific patch) BINDIR_SET is defined to decide
whether or not to use the value of BINDIR.

But why?

If BINDIR is not defined then BINDIR_SET will not be defined. So if
you want to check whether BINDIR is defined why not just check to see
if BINDIR is defined (instead of creating a new variable (BINDIR_SET)
and checking whether it is defined or not)?

Maybe there's something about what you're doing that I don't
understand. But if you're defining BINDIR_SET only if BINDIR is
defined and then using BINDIR_SET to indicate whether or not BINDIR is
defined then I think you're adding complexity for no reason.

PS. I have nothing against _what_ is being done, just the way in which
it is being done.