[CMake] new Makefile generator: make install behaviour

[Brad King]

Alexander Neundorf wrote:
> the rule for make install looks like this: 
>  
> # Special rule to run installation script. 
> install: 
> 	$(CMAKE_COMMAND) -P cmake_install.cmake 
>  
> IOW it doesn't depend on all (which I would have expected to). 
>  
> Shouldn't it be better something like this: 
>  
> # Special rule to run installation script. 
> install: all 
> 	$(CMAKE_COMMAND) -P cmake_install.cmake 

The install rules have never depended on all in any version of CMake.
This is a matter of opinion, but since most other tools do it I don't
have a problem with adding this dependency by default.  I've just
committed changes that enable this, but allow the user to disable it by
setting the CMake variable CMAKE_SKIP_INSTALL_ALL_DEPENDENCY.

-Brad