diff --git a/pkgs/tools/package-management/nix/default.nix b/pkgs/tools/package-management/nix/default.nix
index 55f5b0aedc9..f1dad6379dc 100644
--- a/pkgs/tools/package-management/nix/default.nix
+++ b/pkgs/tools/package-management/nix/default.nix
@@ -5,16 +5,18 @@
 }:
 
 stdenv.mkDerivation rec {
-  name = "nix-1.7";
+  name = "nix-1.8";
 
   src = fetchurl {
     url = "http://nixos.org/releases/nix/${name}/${name}.tar.xz";
-    sha256 = "349163654f2ae3e1a17fb3da7ed164a4cac153728bbe9a26764e17556d3dcc92";
+    sha256 = "a30a5e801bc1cb1019cbc3456d961a307c45c9c588b8692cf1293ea6588ef01c";
   };
 
   nativeBuildInputs = [ perl pkgconfig ];
 
-  buildInputs = [ curl openssl boehmgc sqlite ];
+  buildInputs = [ curl openssl sqlite ];
+
+  propagatedBuildInputs = [ boehmgc ];
 
   # Note: bzip2 is not passed as a build input, because the unpack phase
   # would end up using the wrong bzip2 when cross-compiling.
@@ -22,6 +24,7 @@ stdenv.mkDerivation rec {
   postUnpack =
     '' export CPATH="${bzip2}/include"
        export LIBRARY_PATH="${bzip2}/lib"
+       export CXXFLAGS="-Wno-error=reserved-user-defined-literal"
     '';
 
   configureFlags =
@@ -32,7 +35,6 @@ stdenv.mkDerivation rec {
       --with-www-curl=${perlPackages.WWWCurl}/${perl.libPrefix}
       --disable-init-state
       --enable-gc
-      CFLAGS=-O3 CXXFLAGS=-O3
     '';
 
   makeFlags = "profiledir=$(out)/etc/profile.d";
@@ -55,7 +57,6 @@ stdenv.mkDerivation rec {
         --with-www-curl=${perlPackages.WWWCurl}/${perl.libPrefix}
         --disable-init-state
         --enable-gc
-        CFLAGS=-O3 CXXFLAGS=-O3
       '' + stdenv.lib.optionalString (
           stdenv.cross ? nix && stdenv.cross.nix ? system
       ) ''--with-system=${stdenv.cross.nix.system}'';
@@ -66,9 +67,6 @@ stdenv.mkDerivation rec {
   enableParallelBuilding = true;
 
   meta = {
-    # due to builder args bug; see
-    # https://github.com/NixOS/nix/commit/b224ac15201c57b40ea855f5a98b1bd166c1c7f6
-    broken = stdenv.isDarwin;
     description = "Powerful package manager that makes package management reliable and reproducible";
     longDescription = ''
       Nix is a powerful package manager for Linux and other Unix systems that
diff --git a/pkgs/tools/package-management/nix/unstable.nix b/pkgs/tools/package-management/nix/unstable.nix
index be370808d1e..91c35b59964 100644
--- a/pkgs/tools/package-management/nix/unstable.nix
+++ b/pkgs/tools/package-management/nix/unstable.nix
@@ -1,5 +1,5 @@
 { stdenv, fetchurl, perl, curl, bzip2, sqlite, openssl ? null
-, pkgconfig, boehmgc, perlPackages, bash
+, pkgconfig, boehmgc, perlPackages
 , storeDir ? "/nix/store"
 , stateDir ? "/nix/var"
 }:
@@ -24,7 +24,7 @@ stdenv.mkDerivation rec {
   postUnpack =
     '' export CPATH="${bzip2}/include"
        export LIBRARY_PATH="${bzip2}/lib"
-       export CXXFLAGS="-O3 -Wno-error=reserved-user-defined-literal"
+       export CXXFLAGS="-Wno-error=reserved-user-defined-literal"
     '';
 
   configureFlags =
@@ -35,7 +35,6 @@ stdenv.mkDerivation rec {
       --with-www-curl=${perlPackages.WWWCurl}/${perl.libPrefix}
       --disable-init-state
       --enable-gc
-      CFLAGS=-O3
     '';
 
   makeFlags = "profiledir=$(out)/etc/profile.d";
@@ -58,7 +57,6 @@ stdenv.mkDerivation rec {
         --with-www-curl=${perlPackages.WWWCurl}/${perl.libPrefix}
         --disable-init-state
         --enable-gc
-        CFLAGS=-O3 CXXFLAGS=-O3
       '' + stdenv.lib.optionalString (
           stdenv.cross ? nix && stdenv.cross.nix ? system
       ) ''--with-system=${stdenv.cross.nix.system}'';
diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index 8d069eee709..c75de23c33e 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -12590,10 +12590,13 @@ let
     stateDir = config.nix.stateDir or "/nix/var";
   };
 
+  /*
   nixUnstable = callPackage ../tools/package-management/nix/unstable.nix {
     storeDir = config.nix.storeDir or "/nix/store";
     stateDir = config.nix.stateDir or "/nix/var";
   };
+  */
+  nixUnstable = nixStable;
 
   nixops = callPackage ../tools/package-management/nixops { };