[CMake] empty string and cmake_parse_arguments

[Burlen Loring]

Is it possible to pass "" (an empty string) through 
cmake_parse_arguments?  I'm using cmake 3.4.0.

I found much discussion of a patch to do this in a thread on the cmake 
developer list. however, cmake_parse_arguments still eats the "", and I 
am finding no official documentation about it.

Burlen