nixpkgs/pkgs/development/libraries/zlib/default.nix

{stdenv, fetchurl, static ? false}:

stdenv.mkDerivation (rec {
  name = "zlib-1.2.5";
  
  src = fetchurl {
    url = "http://www.zlib.net/${name}.tar.gz";
    sha256 = "0n7rlgvjn73pyil3s1l6p77m7wkc809n934rnzxv1b1za4pfar30";
  };

  configureFlags = if static then "" else "--shared";

  preConfigure = ''
    if test -n "$crossConfig"; then
      export CC=$crossConfig-gcc
      configureFlags=${if static then "" else "--shared"}
    fi
  '';

  # As zlib takes part in the stdenv building, we don't want references
  # to the bootstrap-tools libgcc (as uses to happen on arm/mips)
  NIX_LDFLAGS = "-static-libgcc";

  crossAttrs = {
    dontStrip = if static then true else false;
  } // (if stdenv.cross.libc == "msvcrt" then {
    configurePhase=''
      installFlags="BINARY_PATH=$out/bin INCLUDE_PATH=$out/include LIBRARY_PATH=$out/lib"
    '';
    makeFlags = [
      "-f" "win32/Makefile.gcc"
      "PREFIX=${stdenv.cross.config}-"
    ] ++ (if static then [] else [ "SHARED_MODE=1" ]);
  } else {});

  # zlib doesn't like the automatic --disable-shared from the Cygwin stdenv.
  cygwinConfigureEnableShared = true;
  
} // stdenv.lib.optionalAttrs (stdenv.system == "i686-cygwin") {
  patches = [ ./no-shared.patch ];
})