ci: Refactor Nix shell files

ci/mkshell.nix

@@ -0,0 +1,12 @@
+{ pkgs }:
+
+with pkgs;
+
+mkShell {
+   buildInputs = [
+       bash file pkgconfig autoconf automake libtool gmp valgrind clang gcc
+   ];
+   shellHook = ''
+       echo Running nix-shell with nixpkgs version: $(nix eval --raw nixpkgs.lib.version)
+   '';
+}

ci/shell-i686.nix

@@ -1,9 +1,4 @@
-with (import <nixpkgs> {}).pkgsi686Linux;
+let
-mkShell {
+  pkgs = (import <nixpkgs> {}).pkgsi686Linux;
-   buildInputs = [
+in
-       bash file pkgconfig autoconf automake libtool gmp valgrind clang gcc
+import ./mkshell.nix { inherit pkgs; }
-   ];
-   shellHook = ''
-       echo Running nix-shell with nixpkgs version: $(nix eval --raw nixpkgs.lib.version)
-   '';
-}

ci/shell.nix

@@ -1,9 +1,4 @@
-with (import <nixpkgs> {});
+let
-mkShell {
+  pkgs = (import <nixpkgs> {});
-   buildInputs = [
+in
-       bash file pkgconfig autoconf automake libtool gmp valgrind clang gcc
+import ./mkshell.nix { inherit pkgs; }
-   ];
-   shellHook = ''
-       echo Running nix-shell with nixpkgs version: $(nix eval --raw nixpkgs.lib.version)
-   '';
-}