Attempting to install Agda via Cabal fails.

I've installed cpphs through Cabal and ~/Library/Haskell/bin is in my path.

~/.cabal/config is default, but in /Library/Frameworks/GHC.framework/Versions/8.4.3-x86_64/usr/lib/ghc-8.4.3 /settings I have changed only ("C compiler supports -no-pie","NO") (from "YES") because that was giving me errors earlier.

The log states: "Please report this as a GHC bug..." so here I am :]