[CMake] Fix doxygen search path.
Doxygen is broken in master (assume also in tagged versions) because the paths to most volumes were wrong.
I added a CMake check so it doesn't happen again.
Edited by Stephan Hageboeck
Doxygen is broken in master (assume also in tagged versions) because the paths to most volumes were wrong.
I added a CMake check so it doesn't happen again.