[patch] Use relative rpath so that the installation and build dirs are relocatable

[Brad King]

On 02/14/2014 06:04 PM, Chandler Carruth wrote:
> This sounds great, but I'd like to hear from Owen and/or  Jim who have
> played with using CMake more heavily on OSX to see if we could use the
> more modern version:
> 
> On Fri, Feb 14, 2014 at 3:01 PM, Rafael Espíndola wrote:
>>     Unfortunately for it to work on OS X we need 2.8.12.

On OS X for @executable_path you could use CMAKE_INSTALL_NAME_DIR:

 http://www.cmake.org/cmake/help/v2.8.12/cmake.html#variable:CMAKE_INSTALL_NAME_DIR

This has been supported for a long time.  CMAKE_MACOSX_RPATH is
for using @rpath in the install_name field of binaries.

-Brad