hpx: 1.6.0 -> 1.7.1

Update HPX from 1.6.0 to 1.7.1. Adds dependency on Asio (new for 1.7.0)
and uses fixed Boost version (1.71.0 is the minimum required by HPX).

pkgs/development/libraries/hpx/default.nix

···
-{ lib, stdenv, fetchFromGitHub, boost, cmake, hwloc, gperftools, pkg-config, python3 }:
+{ lib, stdenv, fetchFromGitHub, asio, boost, cmake, hwloc, gperftools, ninja
+, pkg-config, python3 }:
 
 stdenv.mkDerivation rec {
   pname = "hpx";
-  version = "1.6.0";
+  version = "1.7.1";
 
   src = fetchFromGitHub {
     owner = "STEllAR-GROUP";
     repo = "hpx";
     rev = version;
-    sha256 = "sha256-Fkntfk5AaWtS1x0fXfLSWW/9tvKcCBi1COqgNxurPmk=";
+    sha256 = "1knx7kr8iw4b7nh116ygd00y68y84jjb4fj58jkay7n5qlrxh604";
   };
 
-  buildInputs = [ boost hwloc gperftools ];
+  buildInputs = [ asio boost hwloc gperftools ];
   nativeBuildInputs = [ cmake pkg-config python3 ];
 
   strictDeps = true;

pkgs/top-level/all-packages.nix

···
 
   hound = callPackage ../development/tools/misc/hound { };
 
-  hpx = callPackage ../development/libraries/hpx { };
+  hpx = callPackage ../development/libraries/hpx {
+    boost = boost17x;
+    asio = asio.override { boost = boost17x; };
+  };
 
   hspell = callPackage ../development/libraries/hspell { };