Dave Programmer wrote:
> In a Makefile, I have something like the following:

And your C question was what exactly?

Your question is more likely to be on topic in comp.unix.programmer, I
suspect.

<Off-Topic>

You could look at the manual for (your particular implementation of)
"make" and see if the way it uses environment variables would you

But don't continue the discussion here, please.
</Off-Topic>