Failed import on Mac, PyMUTEX_LOCK(gil->mutex) error

[chepizhko87]

Description
Importing fastddm in python results in the following error message

Python 3.8.3 (default, Jul  2 2020, 11:26:31) 
[Clang 10.0.0 ] :: Anaconda, Inc. on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import fastddm as fddm
Fatal Python error: PyMUTEX_LOCK(gil->mutex) failed
Python runtime state: unknown

[1]    7116 abort      python3

To Reproduce
Steps to reproduce the behavior:

1. Install fastddm with ENABLE_CPP=ON environment variable set in a conda environment.
2. Import fastddm in python

Expected behavior
Import successful.

Desktop (please complete the following information):

• OS: macOS Big Sur
• Version 11.7
• python 3.8.3, compiled with Clang 10.0.0, Anaconda

[enrico-lattuada]

See also this issue in pybind11.
It is possibly due to hard linking of python on mac, which results in error when using anaconda.
The proposed solution is to remove the ${PYTHON_LIBRARIES} in the CMake target_link_libraries command.

[enrico-lattuada]

With @chepizhko87 we tested the solution on mac and linux, with and without active conda environments.
The solution should be checked also on Windows.

[enrico-lattuada]

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