lzip: add unpackCmd hook

pkgs/applications/editors/ed/default.nix

···
     sha256 = "1nqhk3n1s1p77g2bjnj55acicsrlyb2yasqxqwpx0w0djfx64ygm";
   };
 
-  unpackCmd = "tar --lzip -xf";
-
   nativeBuildInputs = [ lzip ];
 
   /* FIXME: Tests currently fail on Darwin:

pkgs/tools/compression/lzip/default.nix

···
 
   configureFlags = "CPPFLAGS=-DNDEBUG CFLAGS=-O3 CXXFLAGS=-O3";
 
+  setupHook = ./lzip-setup-hook.sh;
+
   doCheck = true;
+  enableParallelBuilding = true;
 
   meta = {
     homepage = http://www.nongnu.org/lzip/lzip.html;

pkgs/tools/compression/lzip/lzip-setup-hook.sh

···
+lzipUnpackCmdHook() {
+    [[ "$1" = *.tar.lz ]] && tar --lzip -xf "$1"
+}
+
+unpackCmdHooks+=(lzipUnpackCmdHook)