Previously configureFlags was defined as one giant interpolated string.
Here we refactor this definition to instead use the usual stdenv string
combinators. This seems more in-line with the average nixpkgs expression
and it seems a bit more natural to things of these as lists of flags
rather than monolithic strings.
One should do this when needed executables at run time. It is more
honest and cross-friendly than refering to binutils directly, if one
neeeds the default binary tools for the target platform, rather than
binutils in particular.
...just as we did for binutils. When the underlying issue is resolved
(probably with a configure script patch or lib/systems/parse.nix
change), this should be reverted.
