[CMake] Sharing Modules between different installation of CMake

[Nicholas Yue]

Robert Haines wrote:
> Hi,
>
>>  I am testing different version of CMake on multiple platform to
>> ensure my custom modules works fine on all combination.
>>
>>  I find it troublesome to copy my custom module to all the different
>> ../share/cmake-X.Y/Modules directory
>>
>>  Is there an alternative to telling CMake that there are additional
>> Module search path over and above those it normally searches?
>
> Sure, you can use: set(CMAKE_MODULE_PATH "/path/to/modules"). That 
> path will be checked first so you can use it to override things in the 
> CMake distribution too.
>
> In my projects I put the CMake stuff that I want to distribute with my 
> code into a top-level directory called CMake and use it like so: 
> set(CMAKE_MODULE_PATH "${PROJECT_SOURCE_DIR}/CMake").
>
> Cheers,
> Rob
>
Is there a way to manage this without modifying the CMakeLists.txt file 
e.g. via some environment variable(s)?

Using environment variable allow me to control the version to be use 
which may be different between production and development engineers. It 
also allows me to roll back-forth between versions as need be.

Regards