What creates ld link in devtoolset-4/root/usr/bin?

I have two systems...a development system that was setup for me and a mock environment that I've created to test rpm builds.

I have an issue in my mock environment where it is not seeing the linker included with devtoolset-4. Comparing it to my development system, I find that in /opt/rh/devtoolset-4/root/usr/bin there is a link "ld" which points to /opt/rh/devtoolset-4/root/etc/alternatives/ld, which is also a link which points to /otp/rh/devtoolset-4/root/usr/bin/ld.bfd.

On my mock system, there is no "ld" links in any directories (and as a result, the system only sees /usr/bin/ld).

What creates the links in the above directories? Is that something manually done in a system, or is it a configuration that happens when something is installed?

I've confirmed that the devtoolset-4-runtime and devtoolset-4-binutils packages are installed in my mock environment, as I saw that they were involved with the ld.bfd and alternatives files/dirs.

Thanks for any help.

Rob