lib.kernel: make public

Remove the "version" parameter in order to make it more widely
available.
Starts making some kernel configuration helpers available.
The intent is to be able to better build and check the linux kernel
configuration.

lib/default.nix

@@ -52,6 +52,9 @@ let
     # back-compat aliases
     platforms = systems.doubles;
 
+    # linux kernel configuration
+    kernel = callLibs ./kernel.nix;
+
     inherit (builtins) add addErrorContext attrNames concatLists
       deepSeq elem elemAt filter genericClosure genList getAttr
       hasAttr head isAttrs isBool isInt isList isString length

lib/kernel.nix

@@ -1,12 +1,7 @@
-{ lib, version }:
+{ lib }:
 
 with lib;
 {
-  # Common patterns/legacy
-  whenAtLeast = ver: mkIf (versionAtLeast version ver);
-  whenOlder   = ver: mkIf (versionOlder version ver);
-  # range is (inclusive, exclusive)
-  whenBetween = verLow: verHigh: mkIf (versionAtLeast version verLow && versionOlder version verHigh);
 
 
   # Keeping these around in case we decide to change this horrible implementation :)

pkgs/os-specific/linux/kernel/common-config.nix

@@ -16,10 +16,15 @@
 }:
 
 with stdenv.lib;
-
-  with import ../../../../lib/kernel.nix { inherit (stdenv) lib; inherit version; };
+with stdenv.lib.kernel;
 
 let
+  # Common patterns/legacy
+  whenAtLeast = ver: mkIf (versionAtLeast version ver);
+  whenOlder   = ver: mkIf (versionOlder version ver);
+  # range is (inclusive, exclusive)
+  whenBetween = verLow: verHigh: mkIf (versionAtLeast version verLow && versionOlder version verHigh);
+
 
   # configuration items have to be part of a subattrs
   flattenKConf =  nested: mapAttrs (_: head) (zipAttrs (attrValues nested));

pkgs/os-specific/linux/kernel/hardened-config.nix

@@ -11,8 +11,7 @@
 { stdenv, version }:
 
 with stdenv.lib;
-with import ../../../../lib/kernel.nix { inherit (stdenv) lib; inherit version; };
-
+with stdenv.lib.kernel;
 assert (versionAtLeast version "4.9");
 
 optionalAttrs (stdenv.hostPlatform.platform.kernelArch == "x86_64") {

pkgs/os-specific/linux/kernel/mptcp-config.nix

@@ -1,5 +1,5 @@
 { stdenv }:
-with import ../../../../lib/kernel.nix { inherit (stdenv) lib; version = null; };
+with stdenv.lib.kernel;
 {
     # DRM_AMDGPU = yes;