vim: options for enabling and disabling language support

Closes Homebrew/homebrew#15757.

Signed-off-by: Jack Nagel <jacknagel@gmail.com>

Formula/vim.rb

@@ -11,7 +11,28 @@ class Vim < Formula
 
   env :std # To find interpreters
 
+  LANGUAGES         = %w(lua mzscheme perl python python3 tcl ruby)
+  DEFAULT_LANGUAGES = %w(ruby python)
+
+  LANGUAGES.each do |language|
+    option "with-#{language}", "Build vim with #{language} support"
+    option "without-#{language}", "Build vim without #{language} support"
+  end
+
   def install
+    ENV['LUA_PREFIX'] = HOMEBREW_PREFIX
+
+    language_opts = LANGUAGES.map do |language|
+      with_option    = "with-#{language}"
+      without_option = "without-#{language}"
+
+      if DEFAULT_LANGUAGES.include? language and !build.include? without_option
+        "--enable-#{language}interp"
+      elsif build.include? with_option
+        "--enable-#{language}interp"
+      end
+    end.compact
+
     # Why are we specifying HOMEBREW_PREFIX as the prefix?
     #
     # To make vim look for the system vimscript files in the
@@ -28,10 +49,9 @@ class Vim < Formula
                           "--disable-nls",
                           "--enable-multibyte",
                           "--with-tlib=ncurses",
-                          "--enable-pythoninterp",
-                          "--enable-rubyinterp",
                           "--enable-cscope",
-                          "--with-features=huge"
+                          "--with-features=huge",
+                          *language_opts
     system "make"
 
     # Even though we specified HOMEBREW_PREFIX for configure,