Unable to generate XCode project with CMake

[zfergus]

Describe the bug

CMake fails when targeting XCode using:

cmake .. -GXcode

The error is:

CMake Error in build/_deps/suitesparse-src/CMakeLists.txt:
  The custom command generating

    [path/to]/polyfem/build/_deps/suitesparse-build/FindMETIS.cmake

  is attached to multiple targets:

    cholmod_int
    cholmod_long

  but none of these is a common dependency of the other(s).  This is not
  allowed by the Xcode "new build system".

We might want to create an issue on the SuiteSparse CMake repo as well.

Using make works fine as an alternative, that is call CMake as

cmake ..

Platform

• Windows
• MacOs
• Linux

[teseoch]

Metis is part of the WMTK, which is now optional. In the new version of the WMTK it is not necessary anymore.