Incompatible Find module in CMake 3.14.0

[Christophe Giboudeaux]

Hi,

CMake 3.14.0 comes with a new FindFontconfig.cmake module copied from the kwin 
repository. This happened before the work done to refresh this module prior to 
moving it to ECM.

Variables used in CMake's module are incompatible with the ones used in the 
module currently available in the master branch of the extra-cmake-modules 
repository.

This will cause issues if you're using CMake 3.14.0 to build the soon-to-be-
released ECM 5.57.0 [1]

https://gitlab.kitware.com/cmake/cmake/commit/a3a1e69f8a8 fixes this issue and 
the change will be part of CMake 3.14.1.

[1] https://bugs.kde.org/405887

Christophe