[CMake] adding cmake managed external projects with their config

[Stéphane Ancelot]

Hi,

I have an experimental Bullet package I would like to use, but I don't 
manage to override the system CMAKE_MODULE_PATH for bullet to use the 
new one.

I tried using

ExternalProject_Add (Bullet       SOURCE_DIR "bullet3/build_cmake")


but this does not seem the RIGHT way...

Overriding CMAKE_MODULE_PATH does not work, since cmake at first uses 
it's own.


Any idea ?