fix #1005. fix a regression introduced in eebfda0

Parsing empty documents should raise a SyntaxError when strict parsing
is turned on
Trivial improvements with flags.
List used packaged libraries in post_install_message of a cross-built gem.
Include ports patches in gem.  Ouch.
Show messages loudly about packages libraries in the build process.
fix #852. Make Nokogiri's class cache thread local

Depending on the ScriptingContainer each thread may or may not have its
own runtime. Which means the last runtime that initializes Nokogiri will
insert its RubyClass instances in our class cache. This will cause all
the other threads to see weird behavior as Nokogiri fails to lookup ruby
classes properly. This fix makes the class cache an internal variable
per in the Nokogiri module. Thus, we'll have one cache per runtime
regardless of whether it's shared between threads or not
the java version of the gem shouldn't depend on mini_portile
Close #803. Fix #802.

Fix the documentation of XML::Node#namespace and add more tests to test
the behavior of namespaces
Add support for cross compiling a multi platform (x64-mingw32 and x86-mingw32) fat binary gem and support for native builds on Windows.

This moves all MiniPortile recipes into extconf.rb. This enables
native build on Windows and ensures that all depending libraries
are build with the same compiler version as the C-ext when cross compiling.
Use 'host' as alternative, because host_alias is not set on RubyInstaller-1.9.3
Remove libxslt patches that modify configure.in.

Modifications to configure.in trigger a re-run of autotools,
which adds additional dependencies to nokogiri. This breaks the build
of libxslt when there is a version mismatch between the one used to
release the libxslt tar file and the installed one.

The removed patches itself are IMHO not necessary for nokogiri.
Add missing files to Manifest.txt
Update rake-compiler version to 0.9.2 in order to avoid 'win32/resolv' error.
Move gem post install message into cross compiling callback, so that it
is really used for the packaged fat binary gems.

Avoid adding dependency.yml twice - once per Manifest.txt and once
per add_file_to_gem.
Don't trigger gem task twice in 'rake gem:windows'.

It was called as prerequisites and is called as part of
'rake cross native gem'