Use nixpkgs from flake.lock and support attrs when importing bscpkgs

This makes `nix-build` and friends use the current flake lock instead of
the outdated pinned version we had in `./nixpkgs.nix`

With this, `nix-build -A ovni` and `nix build .#ovni` should produce the
same result.

This will fail if the flake nixpkgs input does not come from NixOS/nixpkgs.
We could use edolstra/flake-compat instead, but it's overkill imho.

Additionally, I made default.nix behave like nixpkgs, so that we can
import bscpkgs à la nixpkgs (Apply overlays and other options that nixpkgs
accepts):

```nix
let pkgs = import bscpkgs { inherit system; }; in <...>
```

default.nix

@@ -1,11 +1,19 @@
 let
   bscOverlay = import ./overlay.nix;
 
-  # Pin the nixpkgs
+  # read flake.lock and determine revision from there
-  nixpkgsPath = import ./nixpkgs.nix;
+  lock = builtins.fromJSON (builtins.readFile ./flake.lock);
-
+  inherit (lock.nodes.nixpkgs.locked) rev narHash;
-  pkgs = import nixpkgsPath {
+  fetchedNixpkgs = builtins.fetchTarball {
-    overlays = [ bscOverlay ];
+    url = "https://github.com/NixOS/nixpkgs/archive/${rev}.tar.gz";
+    sha256 = narHash;
   };
-
+in
-in pkgs
+{ overlays ? [ ]
+, nixpkgs ? fetchedNixpkgs
+, ...
+}@attrs:
+import nixpkgs (
+  (builtins.removeAttrs attrs [ "overlays" "nixpkgs" ]) //
+  { overlays = [ bscOverlay ] ++ overlays; }
+)

nixpkgs.nix

@@ -1,9 +0,0 @@
-let
-  commit = "e4ad989506ec7d71f7302cc3067abd82730a4beb";
-in builtins.fetchTarball {
-    # Descriptive name to make the store path easier to identify
-    name = "nixpkgs-${commit}";
-    url = "https://github.com/nixos/nixpkgs/archive/${commit}.tar.gz";
-    # Hash obtained using `nix-prefetch-url --unpack <url>`
-    sha256 = "sha256-de9KYi8rSJpqvBfNwscWdalIJXPo8NjdIZcEJum1mH0=";
-}

pkgs/bench6/default.nix

@@ -7,7 +7,7 @@
 , mpi
 , tampi
 , gitBranch ? "master"
-, gitURL ? "ssh://git@bscpm03.bsc.es/rarias/bench6.git"
+, gitURL ? "ssh://git@bscpm04.bsc.es/rarias/bench6.git"
 , gitCommit ? "1e6ce2aa8ad7b4eef38df1581d7ec48a8815f85d"
 }:
 

pkgs/cn6/default.nix

@@ -28,7 +28,7 @@ stdenv.mkDerivation rec {
   ] ++ optionals (enableTest) [ mpi clangOmpss2 tampi ];
 
   src = builtins.fetchGit {
-    url = "ssh://git@bscpm03.bsc.es/rarias/cn6.git";
+    url = "ssh://git@bscpm04.bsc.es/rarias/cn6.git";
     ref = "master";
     rev = "c72c3b66b720c2a33950f536fc819051c8f20a69";
   };

pkgs/llvm-ompss2/clang.nix

@@ -14,7 +14,7 @@
 , gcc # needed to set the rpath of libstdc++ for clang-tblgen
 , enableDebug ? false
 , useGit ? false
-, gitUrl ? "ssh://git@bscpm03.bsc.es/llvm-ompss/llvm-mono.git"
+, gitUrl ? "ssh://git@bscpm04.bsc.es/llvm-ompss/llvm-mono.git"
 , gitBranch ? "master"
 , gitCommit ? "8c0d267c04d7fc3fb923078f510fcd5f4719a6cc"
 }:

pkgs/llvm-ompss2/default.nix

@@ -9,12 +9,14 @@
 , ompss2rt ? null
 }:
 
+with lib;
+
 let
   usingNodesAndOmpv = (openmp.pname == "openmp-v" && ompss2rt.pname == "nodes");
   sameNosv = openmp.nosv == ompss2rt.nosv;
 in
 
-assert lib.assertMsg (usingNodesAndOmpv -> sameNosv) "OpenMP-V and NODES must share the same nOS-V";
+assert assertMsg (usingNodesAndOmpv -> sameNosv) "OpenMP-V and NODES must share the same nOS-V";
 
 let
   homevar = if ompss2rt.pname == "nanos6" then "NANOS6_HOME" else "NODES_HOME";
@@ -34,14 +36,15 @@ let
   targetConfig = stdenv.targetPlatform.config;
   inherit gcc;
   cc = clangOmpss2Unwrapped;
+  gccVersion = with versions; let v = gcc.version; in concatStringsSep "." [(major v) (minor v) (patch v)];
 in wrapCCWith {
   inherit cc bintools;
   # extraPackages adds packages to depsTargetTargetPropagated
-  extraPackages = lib.optional (openmp != null) openmp;
+  extraPackages = optional (openmp != null) openmp;
   extraBuildCommands = ''
     echo "-target ${targetConfig}" >> $out/nix-support/cc-cflags
-    echo "-B${gcc.cc}/lib/gcc/${targetConfig}/${gcc.version}" >> $out/nix-support/cc-cflags
+    echo "-B${gcc.cc}/lib/gcc/${targetConfig}/${gccVersion}" >> $out/nix-support/cc-cflags
-    echo "-L${gcc.cc}/lib/gcc/${targetConfig}/${gcc.version}" >> $out/nix-support/cc-ldflags
+    echo "-L${gcc.cc}/lib/gcc/${targetConfig}/${gccVersion}" >> $out/nix-support/cc-ldflags
     echo "-L${gcc.cc.lib}/lib" >> $out/nix-support/cc-ldflags
 
     for dir in ${gcc.cc}/include/c++/*; do
@@ -55,12 +58,12 @@ in wrapCCWith {
 
     wrap clang++  $wrapper $ccPath/clang++
 
-  '' + lib.optionalString (openmp != null) ''
+  '' + optionalString (openmp != null) ''
     echo "export OPENMP_RUNTIME=${ompname}" >> $out/nix-support/cc-wrapper-hook
-  '' + lib.optionalString (ompss2rt != null) ''
+  '' + optionalString (ompss2rt != null) ''
     echo "export OMPSS2_RUNTIME=${rtname}" >> $out/nix-support/cc-wrapper-hook
     echo "export ${homevar}=${ompss2rt}"   >> $out/nix-support/cc-wrapper-hook
-  '' + lib.optionalString (ompss2rt != null && ompss2rt.pname == "nodes") ''
+  '' + optionalString (ompss2rt != null && ompss2rt.pname == "nodes") ''
     echo "export NOSV_HOME=${ompss2rt.nosv}" >> $out/nix-support/cc-wrapper-hook
   '';
 }

pkgs/llvm-ompss2/openmp.nix

@@ -68,6 +68,7 @@ stdenv.mkDerivation rec {
     rm -f $out/lib/libiomp*
   '' + lib.optionalString enableNosv ''
     rm -f $out/lib/libomp.*
+    rm -f $out/libllvmrt/libomp.*
   '';
 
   passthru = {

pkgs/mcxx/git.nix

@@ -23,7 +23,7 @@ stdenv.mkDerivation rec {
   };
 
   src = builtins.fetchGit {
-    url = "ssh://git@bscpm03.bsc.es/mercurium/mcxx";
+    url = "ssh://git@bscpm04.bsc.es/mercurium/mcxx";
     ref = "master";
   };
 

pkgs/mcxx/rarias.nix

@@ -19,7 +19,7 @@ stdenv.mkDerivation rec {
 
   #src = /home/Computational/rarias/mcxx;
   src = builtins.fetchGit {
-    url = "ssh://git@bscpm03.bsc.es/rarias/mcxx";
+    url = "ssh://git@bscpm04.bsc.es/rarias/mcxx";
     rev = "44129a6ac05b8f78b06e9e2eff71438b5ca4d29f";
   };
 

pkgs/nanos6/default.nix

@@ -17,7 +17,7 @@
 , cachelineBytes ? 64
 , enableGlibcxxDebug ? false
 , useGit ? false
-, gitUrl ? "ssh://git@bscpm03.bsc.es/nanos6/nanos6"
+, gitUrl ? "ssh://git@bscpm04.bsc.es/nanos6/nanos6"
 , gitBranch ? "master"
 , gitCommit ? "9f54c988e0a8b9c011d9d526acdb8d76f18fcae4"
 }:

pkgs/nixtools/default.nix

@@ -7,7 +7,7 @@ stdenv.mkDerivation rec {
   pname = "nixtools";
   version = "${src.shortRev}";
   src = builtins.fetchGit {
-    url = "ssh://git@bscpm03.bsc.es/rarias/nixtools";
+    url = "ssh://git@bscpm04.bsc.es/rarias/nixtools";
     ref = "master";
     rev = "a103e392048ace3ed88ce74648b32c9e6ed094da";
   };

pkgs/ovni/default.nix

@@ -6,7 +6,7 @@
 , fetchFromGitHub
 , useGit ? false
 , gitBranch ? "master"
-, gitUrl ? "ssh://git@bscpm03.bsc.es/rarias/ovni.git"
+, gitUrl ? "ssh://git@bscpm04.bsc.es/rarias/ovni.git"
 , gitCommit ? "a7103f8510d1ec124c3e01ceb47d1e443e98bbf4"
 , enableDebug ? false
 # Only enable MPI if the build is native (fails on cross-compilation)

pkgs/tampi/default.nix

@@ -13,7 +13,7 @@
 , enableOvni ? true
 , ovni ? null
 , useGit ? false
-, gitUrl ? "ssh://git@bscpm03.bsc.es/interoperability/tampi.git"
+, gitUrl ? "ssh://git@bscpm04.bsc.es/interoperability/tampi.git"
 , gitBranch ? "master"
 , gitCommit ? "a5c93bf8ab045b71ad4a8d5e2c991ce774db5cbc"
 }: