GHC calls otool on darwin which is contained in the
stdenv.cc.bintools.bintools derivation and thus needs adding to the
runtime PATH of GHC. Since this is toolchain specific technically, we
check for cctools instead of darwin (although I don't know if GHC
or nixpkgs work on macOS without cctools).
This fixes usage of GHC in an environment where otool is not available
and more specifically in stdenvNoCC which is used by writers.writeHaskell.
Resolves#123228.
(cherry picked from commit 118b28a127c79dbae8c513742fbb17f300407a4b)
Previously, the "ar command" in the global config of GHC in nixpkgs is
simply "ar" instead of a proper absolute path in the nix store. This
will result in an "ar: command not found" error when using GHC and cabal
in a pure nix shell. This commit adds the patch and applies to all
pre-9.0 versions.
See output of ghc --info for "ar command" value.
sternenseemann