Remove unused and broken code.

It somehow remained after a rebase conflict.
Merge topic 'compile-defs-debugging' into next

cb2ce4a Remove unused and broken code.
Add target property debugging for COMPILE_DEFINITIONS

Use constructs similar to those for COMPILE_OPTIONS. This is a little
different because there is a command to remove_definitions(), so
we can't populate the equivalent target property until generate-time
in cmGlobalGenerator.
Merge topic 'compile-defs-debugging' into next

381368d Add target property debugging for COMPILE_DEFINITIONS