Python Development module really needed?

[abouteiller]

Original report by Joseph Schuchart (Bitbucket: jschuchart, GitHub: jschuchart).

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I'm building current DPLASMA master on our new system, which provides CMake 3.16.4 and python 2.7.16 installations. Running CMake ends in the following error:

CMake Error at /sw/hawk-rh8/hlrs/non-spack/development/cmake/3.16.4/share/cmake-3.16/Modules/FindPackageHandleStandardArgs.cmake:146 (message):
  Could NOT find Python (missing: Python_LIBRARIES Python_INCLUDE_DIRS
  Development) (found version "2.7.16")
Call Stack (most recent call first):
  /sw/hawk-rh8/hlrs/non-spack/development/cmake/3.16.4/share/cmake-3.16/Modules/FindPackageHandleStandardArgs.cmake:393 (_FPHSA_FAILURE_MESSAGE)
  /sw/hawk-rh8/hlrs/non-spack/development/cmake/3.16.4/share/cmake-3.16/Modules/FindPython.cmake:347 (find_package_handle_standard_args)
  tools/PrecisionGenerator/CMakeLists.txt:5 (find_package)

The problem is that the call to find_package requests the Development module, which for some reason cannot be found on this system. If I remove Development from the call the detection succeeds. The build then runs cleanly. I wonder if this module is really needed in DPLASMA? I see the same problem in the PaRSEC submodule, with the same fix.

[abouteiller]

I think we need it strongly only when using the profiling. In non-profiling cases, the standard python install should be enough to get going and run the tooling we need to do the precision generation.