[CMake] CMake 2.8.12-rc4 ready for testing!

[Robert Maynard]

The CMake 2.8.12 release candidate stream continues!
Thanks to numerous CMake users we uncovered a couple of critical regressions
in RC3. We expect that RC4 will be the final RC unless a new critical,
regression is discovered. You can find the source and binaries here:
  http://www.cmake.org/files/v2.8/?C=M;O=D

Some of the notable changes in this release are:

- Introduced target_compile_options command
  - Specify compile options to use when compiling a given target. Supports
    PUBLIC, PRIVATE, and INTERFACE options. PRIVATE and PUBLIC items will
    populate the COMPILE_OPTIONS property of the target. PUBLIC and
    INTERFACE items will populate the INTERFACE_COMPILE_OPTIONS property
    of the target. Supports generator expressions.
- Introduced add_compile_options command
  - Adds options to the compiler command line for sources in the
    current directory and below. Supports generator expressions.
- Introduced CMake Policy CMP0021:
    - It is now an error to add relative paths to the INCLUDE_DIRECTORIES
      target property.
- Introduced CMake Policy CMP0022:
  - Target properties matching (IMPORTED_)LINK_INTERFACE_LIBRARIES(_<CONFIG>)
    are ignored, and will no longer be populated by the target_link_libraries
    command. It is now an error to populate the properties directly in user
    code. Instead use the INTERFACE keyword with target_link_libraries, or
    the target property INTERFACE_LINK_LIBRARIES.
- Introduced CMake Policy CMP0023:
  - Plain and keyword target_link_libraries signatures cannot be mixed for a
    given target when this policy is enabled. Once PUBLIC,PRIVATE, or
    INTERFACE keywords are used, all subsequent target_link_libraries calls
    to the target must use one of these keywords.
- Introduced: Support for RPATH under OSX
  - Please see the blog post by Clinton Stimpson about using RPATH on OSX
    (http://www.kitware.com/blog/home/post/510)

- CMake: New PUBLIC PRIVATE and INTERFACE options for target_link_libraries
- CMake: New ALIAS targets feature
- CMake: Automatically process Headers directory of Apple Frameworks as
         a usage requirement
- CMake: File command now supports the GENERATE command to produce files at
         generate time
- CMake: target_include_directories now supports the SYSTEM parameter
- CMake: Add support for Java in cross compilation toolchains
- CMake: Improved support for the IAR toolchain
- CMake: Improved support for the ARM toolchain under Visual Studio
- CMake: Improvements to the Visual Studio Generators Including
  - Separate compiler and linker PDB files
  - Support for subdirectory MSBuild projects
  - Support for assembly code to VS10
  - Support for Windows CE to VS11
- CMake: Added COMPILE_OPTIONS target property.
- CMake: Added INTERFACE_LINK_LIBRARIES added as a property to targets
- CMake: Now supports .zip files with the tar command
- CMake: try_compile now supports multiple source files
- CMake: Optimized custom command dependency lookup
- CMake: Removal of configured files will retrigger CMake when issuing a
         build command
- CMake: Ninja now tracks custom command generated files that aren't listed
         as output
- CMake: Added generator expression support for compiler versions
- CMake-Gui: Add search functions for Output window
- CTest: Improved memory checker support
- FindGTK2: General Improvements
- FindCUDA: Multiple improvements to the custom commands


The bug tracker change log page for this version is at:
http://public.kitware.com/Bug/changelog_page.php?version_id=112

The complete list of changes in RC4 since RC3 can be found at:
http://www.cmake.org/Wiki/CMake/ChangeLog

As this is expected to be the last RC release please test it and report any
regressions to the list or the bug tracker.

Thanks