There is no need to duplicate these in all cmLocalGenerators.

Rename the symbols according to current conventions.

Add explicit calls to Set{Source,Binary}Directory with empty strings
in order to trigger the population of the components containers with
the current working directory in cmLocalGenerator.  Having
directories set to empty is a special case in CMake, which is relied
on for the `if(CMAKE_BINARY_DIR)` condition at the end of
CMakeDetermineSystem.cmake.