anchor.diff:  { lib, stdenv, fetchFromGitHub, cmake, curl, openssl, zlib
  +, aws-c-common, aws-c-event-stream, aws-checksums
   , CoreAudio, AudioToolbox
   , # Allow building a limited set of APIs, e.g. ["s3" "ec2"].
     apis ? ["*"]
  
positive.code:   separateDebugInfo = stdenv.isLinux;
  
    nativeBuildInputs = [ cmake curl ];
    buildInputs = [ zlib curl openssl ]
      ++ lib.optionals (stdenv.isDarwin &&
                          ((builtins.elem "text-to-speech" apis) ||
                           (builtins.elem "*" apis)))
           [ CoreAudio AudioToolbox ];
  
    cmakeFlags =
         lib.optional (!customMemoryManagement) "-DCUSTOM_MEMORY_MANAGEMENT=0"
      ++ lib.optional (stdenv.buildPlatform != stdenv.hostPlatform) "-DENABLE_TESTING=OFF"
      ++ lib.optional (apis != ["*"])
        "-DBUILD_ONLY=${lib.concatStringsSep ";" apis}";
  
    enableParallelBuilding = true;
  
    # Behold the escaping nightmare below on loaderVar o.O
    preBuild =
      ''
        # Ensure that the unit tests can find the *.so files.
        for i in testing-resources aws-cpp-sdk-*; do
          export ${loaderVar}=$(pwd)/$i:''${${loaderVar}}
        done
      '';
  
    preConfigure =
      ''
        rm aws-cpp-sdk-core-tests/aws/auth/AWSCredentialsProviderTest.cpp
      '';
  
    NIX_CFLAGS_COMPILE = [ "-Wno-error=noexcept-type" ];
  
    __darwinAllowLocalNetworking = true;
  
    meta = {
      description = "A C++ interface for Amazon Web Services";
      homepage = https://github.com/awslabs/aws-sdk-cpp;
      license = lib.licenses.asl20;
      platforms = lib.platforms.linux ++ lib.platforms.darwin;
      maintainers = [ lib.maintainers.eelco ];
    };
  }
  
negative.code:   customMemoryManagement ? true
  }:
  
  stdenv.mkDerivation rec {
    name = "aws-sdk-cpp-${version}";
    version = "1.7.49";
  
    src = fetchFromGitHub {
      owner = "awslabs";
      repo = "aws-sdk-cpp";
      rev = version;
      sha256 = "09j1y82jvi69mj7h751wg0zlyf3n8s2zgfn5p85v4659pl4jgqmf";
    };
  
    # FIXME: might be nice to put different APIs in different outputs
  