Add method to install go packages

Several go related tools can be used within emacs, such as:
gocode, godef, goimports, golint, goflymake, etc.

The el-get-go method lets the 'go get' command take care of
downloading and building such tools.  The main advantage is letting
go get take care of resolving dependecies and building the binary,
rather than wedging into the :build property.

el-get-methods.el

@@ -34,6 +34,7 @@
 (require 'el-get-git)
 (require 'el-get-github)
 (require 'el-get-git-svn)
+(require 'el-get-go)
 (require 'el-get-hg)
 (require 'el-get-http)
 (require 'el-get-http-tar)

el-get.texi

@@ -161,7 +161,7 @@ methods that targets @code{apt-get}, @code{brew}, @code{builtin},
 @code{bzr}, @code{cvs}, @code{darcs}, @code{elpa}, @code{emacsmirror},
 @code{emacswiki}, @code{fink}, @code{fossil}, @code{git} and
 @code{git-svn}, @code{github} @code{github-tar} and @code{github-zip},
-@code{hg}, @code{http} @code{http-tar} and @code{http-zip},
+@code{go}, @code{hg}, @code{http} @code{http-tar} and @code{http-zip},
 @code{pacman} and @code{svn}.
 
 @item Notification

methods/el-get-go.el

+;;; el-get --- Manage the external elisp bits and pieces you depend upon
+;;
+;; Copyright (C) 2010-2011 Dimitri Fontaine
+;;
+;; Author: Dimitri Fontaine <dim@tapoueh.org>
+;; URL: http://www.emacswiki.org/emacs/el-get
+;; GIT: https://github.com/dimitri/el-get
+;; Licence: WTFPL, grab your copy here: http://sam.zoy.org/wtfpl/
+;;
+;; This file is NOT part of GNU Emacs.
+;;
+;; Install
+;;     Please see the README.md file from the same distribution
+
+(defcustom el-get-go (executable-find "go")
+  "The go executable."
+  :group 'el-get
+  :type 'file)
+
+(defcustom el-get-go-install-hook nil
+  "Hook run after go install."
+  :group 'el-get
+  :type 'hook)
+
+(defun el-get-go-install (package url post-install-fun)
+  "go install PACKAGE"
+  (let* ((gopath (getenv "GOPATH"))
+         (source (el-get-package-def package))
+         (pkgname (el-get-as-string (plist-get source :pkgname)))
+         (pdir (el-get-package-directory package))
+         (name (format "*go get %s*" package))
+	 (ok   (format "Package %s installed." package))
+	 (ko   (format "Could not install package %s." package)))
+    (unless (file-directory-p pdir)
+      (make-directory pdir))
+    (setenv "GOPATH" pdir)
+    (el-get-start-process-list
+     package
+     `((:command-name ,name
+		      :buffer-name ,name
+                      :default-directory ,el-get-dir
+		      :program ,el-get-go
+		      :args ("get" "-v" "-u" ,pkgname)
+		      :message ,ok
+		      :error ,ko))
+     post-install-fun)
+    (setenv "GOPATH" gopath)))
+
+(el-get-register-method :go
+  :install #'el-get-go-install
+  :update #'el-get-go-install
+  :remove #'el-get-rmdir
+  :install-hook #'el-get-go-install-hook)
+
+(provide 'el-get-go)