From 3c8ae01a45196759cd01de639f0d200fdfcb6d77 Mon Sep 17 00:00:00 2001
From: John Ericson <John.Ericson@Obsidian.Systems>
Date: Tue, 20 Mar 2018 11:46:12 -0400
Subject: [PATCH 1/4] lib: Make `platforms.all` actually match all platforms

Otherwise obscure cross-compilations are hampered. `all` breaks all but
the initial derivation (which we can't even write yet) in an open world
setting however, so we really shouldn't have it.
---
 lib/systems/for-meta.nix | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/lib/systems/for-meta.nix b/lib/systems/for-meta.nix
index fa713b1e613..3402fa0ca19 100644
--- a/lib/systems/for-meta.nix
+++ b/lib/systems/for-meta.nix
@@ -4,8 +4,8 @@ let
   inherit (lib.systems.inspect) patterns;
 
 in rec {
-  inherit (lib.systems.doubles) all mesaPlatforms;
-  none = [];
+  all     = [ {} ]; # `{}` matches anything
+  none    = [];
 
   arm     = [ patterns.isArm ];
   aarch64 = [ patterns.isAarch64 ];
@@ -24,4 +24,6 @@ in rec {
   netbsd  = [ patterns.isNetBSD ];
   openbsd = [ patterns.isOpenBSD ];
   unix    = patterns.isUnix; # Actually a list
+
+  inherit (lib.systems.doubles) mesaPlatforms;
 }

From d9a1800239620425ef3608487f87002b1a4d1437 Mon Sep 17 00:00:00 2001
From: John Ericson <John.Ericson@Obsidian.Systems>
Date: Tue, 20 Mar 2018 12:31:07 -0400
Subject: [PATCH 2/4] lib: Add `lib.platforms.windows`

---
 lib/systems/for-meta.nix | 1 +
 1 file changed, 1 insertion(+)

diff --git a/lib/systems/for-meta.nix b/lib/systems/for-meta.nix
index 3402fa0ca19..63f24b46535 100644
--- a/lib/systems/for-meta.nix
+++ b/lib/systems/for-meta.nix
@@ -24,6 +24,7 @@ in rec {
   netbsd  = [ patterns.isNetBSD ];
   openbsd = [ patterns.isOpenBSD ];
   unix    = patterns.isUnix; # Actually a list
+  windows = [ patterns.isWindows ];
 
   inherit (lib.systems.doubles) mesaPlatforms;
 }

From e49c14c35b73d464d0b3070de7802ca309f7bb6b Mon Sep 17 00:00:00 2001
From: John Ericson <John.Ericson@Obsidian.Systems>
Date: Tue, 20 Mar 2018 12:31:43 -0400
Subject: [PATCH 3/4] libatomic_ops: Allow Building on Windows too

---
 pkgs/development/libraries/libatomic_ops/default.nix | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pkgs/development/libraries/libatomic_ops/default.nix b/pkgs/development/libraries/libatomic_ops/default.nix
index fe4cd3ca0a9..04cf1c1e696 100644
--- a/pkgs/development/libraries/libatomic_ops/default.nix
+++ b/pkgs/development/libraries/libatomic_ops/default.nix
@@ -28,6 +28,6 @@ stdenv.mkDerivation rec {
     description = ''A library for semi-portable access to hardware-provided atomic memory update operations'';
     license = stdenv.lib.licenses.gpl2Plus ;
     maintainers = [stdenv.lib.maintainers.raskin];
-    platforms = stdenv.lib.platforms.unix;
+    platforms = with stdenv.lib.platforms; unix ++ windows;
   };
 }

From 65e24f22e69ea18b5ec638f89a87e070d4e2154a Mon Sep 17 00:00:00 2001
From: John Ericson <John.Ericson@Obsidian.Systems>
Date: Tue, 20 Mar 2018 11:51:37 -0400
Subject: [PATCH 4/4] haskell-generic-builder: Default to window + unix
 platforms,

Since GHC is a cross compiler, it's perfectly possible to make haskell
binaries on platforms without GHCs. `windows ++ unix` seems good enough
for now.

Also don't default `hydraPlatforms` to `platforms`. The former must be a
list of systems (strings), but the latter is a list of systems or
patterns.
---
 pkgs/development/haskell-modules/generic-builder.nix | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/pkgs/development/haskell-modules/generic-builder.nix b/pkgs/development/haskell-modules/generic-builder.nix
index 1a788ae642e..3cdf2e2252b 100644
--- a/pkgs/development/haskell-modules/generic-builder.nix
+++ b/pkgs/development/haskell-modules/generic-builder.nix
@@ -34,8 +34,8 @@ in
 , enableStaticLibraries ? true
 , extraLibraries ? [], librarySystemDepends ? [], executableSystemDepends ? []
 , homepage ? "http://hackage.haskell.org/package/${pname}"
-, platforms ? ghc.meta.platforms
-, hydraPlatforms ? platforms
+, platforms ? with stdenv.lib.platforms; unix ++ windows # GHC can cross-compile
+, hydraPlatforms ? null
 , hyperlinkSource ? true
 , isExecutable ? false, isLibrary ? !isExecutable
 , jailbreak ? false
@@ -404,7 +404,7 @@ stdenv.mkDerivation ({
          // optionalAttrs broken               { inherit broken; }
          // optionalAttrs (description != "")  { inherit description; }
          // optionalAttrs (maintainers != [])  { inherit maintainers; }
-         // optionalAttrs (hydraPlatforms != platforms) { inherit hydraPlatforms; }
+         // optionalAttrs (hydraPlatforms != null) { inherit hydraPlatforms; }
          ;
 
 }