Is it possible to specify a different location for the location of the libraries installed in `build-native`.

Hello,

I was wondering if it is possible to specify a different location to `build-toolchain.sh` for the libraries that get installed into `build-native` during `build-prerequisites.sh` (expat, gmp, isl, etc.). I see that `build-toolchain.sh` expects those libraries to exist in `build-native` but is it possible to provide it a different location without changing the file?

Let me back up and explain what has prompted this question. I am trying to write a homebrew formula to build the toolchain. I originally just used the exact steps that are laid out in the how-to pdf but had to make some changes. Because homebrew already has formulas for all of the libraries that get installed during `build-prerequisites.sh`, I have to use those libraries instead of what gets installed by `build-prerequisites.sh`. This works, but only if I manually change the location where `build-toolchain.sh` thinks those libraries should be. I wanted to check to see if there is already a way to specify a different location that I am just not aware of, or see if that is something you would consider adding as an option to the script?

So to summarize: if I already have the prerequisite libraries installed on my machine, is there a way to point `build-toolchain.sh` to them? And if there isn't, would you consider adding that functionality through an option?