If we try to do that, clang would end up calling <triplet>-gcc with the
same arguments. In our setup, this recursively ends up calling clang again,
ending up with infinite recursion.
We quote each passed through argument, and escape quote chars in them.
For cases when the passed through argument ends with a backslash, this
fails though, since whatever is unescaping it doesn't seem to handle
double backslashes for escaping backslashes themselves.
This allows non-msys build systems to use the triplet prefixed
compiler frontends on windows.
Keep the old shell script version as well, for easier hackability
on unix platforms.
Martin Storsjö