Platform not detected correctly on Red Hat Enterprise Linux 7

Today I tried installing a new version of GHC using ghcup on RHEL:

$ ghcup install 8.10.1
[ Warn  ] New GHC version available: 8.10.1. To upgrade, run 'ghcup install 8.10.1'
[ Info  ] downloading: https://downloads.haskell.org/~ghc/8.10.1/ghc-8.10.1-x86_64-fedora27-linux.tar.xz

This fails with

error while loading shared libraries: libtinfo.so.6: cannot open shared object file: No such file or directory

because RHEL 7 has an older version of libtinfo.so than Fedora 27.

This lead me to check https://downloads.haskell.org/~ghc/8.10.1, where I could see that there is a version of GHC for centos7, which is the version that works on RHEL 7, because CentOS is a copy of RHEL.

Hence, I was able to make the install work by running:

$ ghcup install -p x86_64-centos7-linux 8.10.1

Now, my proposal is that when running on RHEL the platform should be detected as CentOS, not Fedora. I would submit a pull request to get this fixed if I knew where to start, so hopefully someone can point me in the right direction.