Support appengine-jruby.

The problem was that File.expand_path("../../..", __FILE__) broke
because appengine-jruby packs everything into JARs.
This meant that __FILE__ was a fancy URL,
which caused File.expand_path to choke when used as the second argument.

doc-src/HAML_CHANGELOG.md

@@ -3,6 +3,14 @@
 * Table of contents
 {:toc}
 
+## 3.0.10 (Unreleased)
+
+### Appengine-JRuby Support
+
+The way we determine the location of the Haml installation
+no longer breaks the version of JRuby
+used by [`appengine-jruby`](http://code.google.com/p/appengine-jruby/).
+
 ## 3.0.9
 
 [Tagged on GitHub](http://github.com/nex3/haml/commit/3.0.9).

doc-src/SASS_CHANGELOG.md

@@ -5,6 +5,14 @@
 
 ## 3.0.10 (Unreleased)
 
+### Appengine-JRuby Support
+
+The way we determine the location of the Haml installation
+no longer breaks the version of JRuby
+used by [`appengine-jruby`](http://code.google.com/p/appengine-jruby/).
+
+### Other Improvements
+
 * When using `sass-convert --from sass2 --to sass --recursive`,
   suggest the use of `--in-place` as well.
 

lib/haml/root.rb

@@ -3,5 +3,5 @@ module Haml
   # This may be overridden by the package manager
   # if the lib directory is separated from the main source tree.
   # @api public
-  ROOT_DIR = File.expand_path("../../..", __FILE__)
+  ROOT_DIR = File.expand_path(File.join(__FILE__, "../../.."))
 end