* Allow overriding install path with CMAKE_INSTALL_PREFIX.
* make sure js2min.py can be found when building out of source.
* Replace empty macros with void(0).
Expressions like "debug(x) && foo()" fail if debug(x) is an empty macro.
* Make sure node-natives.h creation is deterministic.
* Fix version string.
The copyright header made the node_version.h file larger
than the previously set file read limit.
This ensures that the check_function_exists() for fdatasync in the
libeio CMakeLists.txt is not run, since that fails on some versions of
OSX (http://public.kitware.com/Bug/view.php?id=10044).
Squashed commit of ca128f7dcd28cbcfba154c8577ed54d4aa71dd02 with
contributions from Mark Constable (markc@renta.net) and Daniel Gröber
(darklord@darkboxed.org).