[CMake] How to make dependency scanner ignore some paths?

[Pavel Shevaev]

Guys, what is the best way to to make the dependency scanner ignore some paths?

For example, I'm using boost in my project but I really don't want the
dependency scanner to take it into account since it changes rarely(or
never).

For some time I've been using the following trick:

include_regular_expression("^.*(h|cpp|inl|inc)$")

...and it worked since my application and all libraries(except boost)
are using these file extensions(while boost uses .hpp).

But now I have to use another library in the project which uses .hpp
extension. I had to comment the include_regular_expression line and
now the dry run of the cmake takes 2 times longer(was 9 secs, now 22
secs). It's quite annoying especially when you know that it used to be
faster :)

Is there any solution for this? It's ok for me to use the latest
cmake's features(2.8.0 as of this writing).

-- 
Best regards, Pavel