programs-info: add module and run install-info on system packages.

Fixes #25

default.nix

@@ -47,6 +47,7 @@ let
         ./modules/programs/bash.nix
         ./modules/programs/fish.nix
         ./modules/programs/man.nix
+        ./modules/programs/info
         ./modules/programs/nix-script.nix
         ./modules/programs/tmux.nix
         ./modules/programs/vim.nix

modules/environment/default.nix

@@ -43,6 +43,12 @@ in {
       description = "A list of profiles used to setup the global environment.";
     };
 
+    environment.postBuild = mkOption {
+      type = types.lines;
+      default = "";
+      description = "Commands to execute when building the global environment.";
+    };
+
     environment.extraOutputsToInstall = mkOption {
       type = types.listOf types.str;
       default = [];
@@ -125,7 +131,6 @@ in {
     environment.pathsToLink =
       [ "/bin"
         "/lib"
-        "/share/info"
         "/share/locale"
       ];
 
@@ -146,7 +151,7 @@ in {
     system.path = pkgs.buildEnv {
       name = "system-path";
       paths = cfg.systemPackages;
-      inherit (cfg) pathsToLink extraOutputsToInstall;
+      inherit (cfg) postBuild pathsToLink extraOutputsToInstall;
     };
 
     system.build.setEnvironment = concatStringsSep "\n" exportVariables;

modules/programs/info/default.nix

@@ -0,0 +1,35 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  cfg = config.programs.info;
+in
+
+{
+  options = {
+    programs.info.enable = mkOption {
+      type = types.bool;
+      default = true;
+      description = "Whether to enable info pages and the <command>info</command> command.";
+    };
+  };
+
+  config = mkIf cfg.enable {
+
+    environment.systemPackages = [ pkgs.texinfoInteractive ];
+
+    environment.pathsToLink = [ "/info" "/share/info" ];
+    environment.extraOutputsToInstall = [ "info" ];
+
+    environment.postBuild = ''
+      if test -w $out/share/info; then
+        shopt -s nullglob
+        for i in $out/share/info/*.info $out/share/info/*.info.gz; do
+          ${pkgs.texinfoInteractive}/bin/install-info $i $out/share/info/dir
+        done
+      fi
+    '';
+
+  };
+}