Refactor Idris packaging infrastructure

The main two changes are

1. Completely rewrite how with-packages works to remove use of envHooks
2. The package description is now an idris specific set rather than
    being a subset of the arguments to mkDerivation. This mirrors the
    way Haskell packages are treated.

pkgs/development/idris-modules/build-builtin-package.nix

@@ -1,4 +1,4 @@
-# Build one of the packages that come with idris
+# Build one of the packages that comes with idris
 # name: The name of the package
 # deps: The dependencies of the package
 { idris, build-idris-package, lib }: name: deps:
@@ -6,20 +6,16 @@ let
   inherit (builtins.parseDrvName idris.name) version;
 in
 build-idris-package {
-  name = "${name}-${version}";
-
-  propagatedBuildInputs = deps;
 
+  inherit name version;
   inherit (idris) src;
 
+  idrisDeps = deps;
+
   postUnpack = ''
     sourceRoot=$sourceRoot/libs/${name}
   '';
 
-  postPatch = ''
-    sed -i ${name}.ipkg -e "/^opts/ s|-i \\.\\./|-i $IDRIS_LIBRARY_PATH/|g"
-  '';
-
   meta = idris.meta // {
     description = "${name} builtin Idris library";
   };