PDB_OUTPUT_DIRECTORY_<CONFIG>
-----------------------------

Per-configuration output directory for MS debug symbols .pdb files.

This is a per-configuration version of PDB_OUTPUT_DIRECTORY, but
multi-configuration generators (VS, Xcode) do NOT append a
per-configuration subdirectory to the specified directory.  This
property is initialized by the value of the variable
CMAKE_PDB_OUTPUT_DIRECTORY_<CONFIG> if it is set when a target is
created.

This property is not implemented by the Visual Studio 6 generator.
