Specify Python binding language in CMakeLists.txt

[garth-wells]

No description provided.

[francesco-ballarin]

Are we sure that we want to do this change right now?

After this change, my weekly FEM on Colab build fails with

Building wheels for collected packages: fenics-dolfinx
  Building wheel for fenics-dolfinx (pyproject.toml): started
  Building wheel for fenics-dolfinx (pyproject.toml): finished with status 'error'
  error: subprocess-exited-with-error
  
  × Building wheel for fenics-dolfinx (pyproject.toml) did not run successfully.
  │ exit code: 1
  ╰─> [70 lines of output]
      *** scikit-build-core 0.11.3 using CMake 4.0.0 (wheel)
      *** Configuring CMake...
      loading initial cache file /tmp/tmprfxbd2vk/build/CMakeInit.txt
      Re-run cmake no build system arguments
      -- The CXX compiler identification is GNU 12.3.0
      -- Detecting CXX compiler ABI info
      -- Detecting CXX compiler ABI info - done
      -- Check for working CXX compiler: /usr/local/bin/mpicxx - skipped
      -- Detecting CXX compile features
      -- Detecting CXX compile features - done
      -- Found Python: /usr/bin/python3 (found version "3.11.12") found components: Interpreter Development Development.Module Development.Embed
      -- Found MPI_CXX: /usr/local/bin/mpicxx (found version "3.1")
      -- Found MPI: TRUE (found version "3.1")
      -- Performing Test CMAKE_HAVE_LIBC_PTHREAD
      -- Performing Test CMAKE_HAVE_LIBC_PTHREAD - Success
      -- Found Threads: TRUE
      -- Found Boost 1.88.0 at /usr/local/lib/cmake/Boost-1.88.0
      --   Requested configuration: REQUIRED
      -- Found boost_headers 1.88.0 at /usr/local/lib/cmake/boost_headers-1.88.0
      -- Checking for Basix hints with /usr/bin/python3
      -- Adding /usr/local/lib/python3.11/site-packages/basix to Basix search hints
      -- HDF5: Using hdf5 compiler wrapper to determine C configuration
      -- Found HDF5: /usr/local/lib/libhdf5.so;/usr/lib/x86_64-linux-gnu/libsz.so;/usr/lib/x86_64-linux-gnu/libz.so;/usr/lib/x86_64-linux-gnu/libdl.a;/usr/lib/x86_64-linux-gnu/libm.so (found version "1.14.3") found components: C
      -- HDF5_DIR: HDF5_DIR-NOTFOUND
      -- HDF5_DEFINITIONS:
      -- HDF5_INCLUDE_DIRS:
      -- HDF5_LIBRARIES: /usr/local/lib/libhdf5.so;/usr/lib/x86_64-linux-gnu/libsz.so;/usr/lib/x86_64-linux-gnu/libz.so;/usr/lib/x86_64-linux-gnu/libdl.a;/usr/lib/x86_64-linux-gnu/libm.so
      -- HDF5_HL_LIBRARIES:
      -- HDF5_C_DEFINITIONS:
      -- HDF5_C_INCLUDE_DIR:
      -- HDF5_C_INCLUDE_DIRS:
      -- HDF5_C_LIBRARY:
      -- HDF5_C_LIBRARIES: /usr/local/lib/libhdf5.so;/usr/lib/x86_64-linux-gnu/libsz.so;/usr/lib/x86_64-linux-gnu/libz.so;/usr/lib/x86_64-linux-gnu/libdl.a;/usr/lib/x86_64-linux-gnu/libm.so
      -- HDF5_C_HL_LIBRARY:
      -- HDF5_C_HL_LIBRARIES:
      -- Defined targets (if any):
      -- ... hdf5::hdf5
      -- Found PkgConfig: /usr/bin/pkg-config (found version "0.29.2")
      -- Checking for one of the modules 'PETSc;petsc'
      -- Checking for one of the modules 'SLEPc;slepc'
      -- Found ADIOS2: /usr/local/lib/cmake/adios2/adios2-config.cmake (found suitable version "2.10.2", minimum required is "2.8.1") found components: CXX
      -- Found DOLFINx at /usr/local/lib/cmake/dolfinx
      -- Performing Test HAVE_PEDANTIC
      -- Performing Test HAVE_PEDANTIC - Success
      -- Found petsc4py include directory at /usr/local/lib/python3.11/dist-packages/petsc4py/include
      -- Found mpi4py include directory at /usr/local/lib/python3.11/dist-packages/mpi4py/include
      -- Configuring done (1.7s)
      CMake Error at /usr/local/lib/cmake/adios2/adios2-cxx11-targets.cmake:69 (set_target_properties):
        The link interface of target "adios2::cxx11_mpi" contains:
      
          MPI::MPI_C
      
        but the target was not found.  Possible reasons include:
      
          * There is a typo in the target name.
          * A find_package call is missing for an IMPORTED target.
          * An ALIAS target is missing.
      
      Call Stack (most recent call first):
        /usr/local/lib/cmake/adios2/adios2-config-common.cmake:211 (include)
        /usr/local/lib/cmake/adios2/adios2-config.cmake:29 (include)
        /usr/lib/python3.11/site-packages/cmake/data/share/cmake-4.0/Modules/CMakeFindDependencyMacro.cmake:78 (find_package)
        /usr/local/lib/cmake/dolfinx/DOLFINXConfig.cmake:123 (find_dependency)
        CMakeLists.txt:26 (find_package)
      
      
      -- Generating done (0.0s)
      CMake Generate step failed.  Build files cannot be regenerated correctly.
      
      *** CMake configuration failed
      [end of output]
  
  note: This error originates from a subprocess, and is likely not a problem with pip.
  ERROR: Failed building wheel for fenics-dolfinx

adios2 related discussions are in ornladios/ADIOS2#4255 and ornladios/ADIOS2#4082 but it seems to me that the corresponding commit ornladios/ADIOS2@8afa8af hasn't made it into a release yet.

[garth-wells]

Spack fails without the change.

[francesco-ballarin]

OK, not a big deal: I easily backported ornladios/ADIOS2@8afa8af onto v2.10.2 of adios2.

cc-ing @drew-parsons @minrk , as we/they may need to do a similar job if the next release of dolfinx happens before v2.11 of adios2.