Output directory in which to build |XXX| target files.

This property specifies the directory into which |xxx| target files
should be built.  Multi-configuration generators (VS, Xcode) append a
per-configuration subdirectory to the specified directory.

.. include:: TARGET_FILE_TYPES.txt

This property is initialized by the value of the variable
|CMAKE_XXX_OUTPUT_DIRECTORY| if it is set when a target is created.
