Fixed broken install prefix setting

[metacollin]

This does not work for macOS users. It will try to install to /usr/local/share/kicad (which does not exist) and fails without installing anything.

This is caused by how CMAKE_INSTALL_PREFIX is being handled. Without using FORCE because the project ( ) command, whose job is to setup the basic variables needed, will have already set CMAKE_INSTALL_PREFIX. Some older versions of cmake with an incomplete implementation of project don't set the install prefix, allowing this to accidentally work. That is not the intended behavior however, nor does it work with recent versions of cmake.

This commit fixes the problem by using the canonical way to handle the CMAKE_INSTALL_PREFIX according to the cmake developers: https://public.kitware.com/pipermail/cmake/2010-December/041135.html

[CLAassistant]

All committers have signed the CLA.

[poeschlr]

The same change for the symbol repo is done in KiCad/kicad-symbols#409

@metacollin does the 3d model repo also require something similar?

[poeschlr]

I asked the developers for input on this one. (As i don't know enough about cmake)
https://lists.launchpad.net/kicad-developers/msg35113.html

[metacollin]

@poeschlr Thank you for taking the time to post this on the mailing list, I'm reading through the thread right now. It looks like I might need to use something other than CMAKE_INSTALL_PREFIX_INITIALIZED_TO_DEFAULT to achieve a similar effect.

Anyway, thanks again!

[antoniovazquezblanco]

What is the status on this issue @metacollin?
It seems you have been trying to solve two different issues and one have been fixed by the following line:

kicad-footprints/CMakeLists.txt

Line 46 in 43bf2cf

file (GLOB PRETTY_DIRS "*.pretty")

But I do not know enough to check wether the other issue is gone.

Thank you!

[poeschlr]

The devs where not happy with the proposed solution so i would guess this can be closed.