Hi,
nestsimulator-2.18.0 fails PyNEST installation as requesting  libgsl.so.23  while libgsl.so.25 is available (see brelow --1-- log of installcheck for PyNEST tests)
cmake reports no errors with GSL (see bleow --2-- log extract  of cmake output )
configuration: linux manjaro latest system update 2019-09-05
Sorry for my ignorance : is there a way to force linking with most recent gsl library ? 
Or is it necessary to install also the old library version somehow? If then how ?
Thank you in advance for any help
Samuel Bottani
--1--
Phase 7: Running PyNEST tests.
------------------------------
  Using nosetests.
  Failure: ImportError (libgsl.so.23: cannot open shared object file: No such file or directory) ... ERROR
  Failure: ImportError (libgsl.so.23: cannot open shared object file: No such file or directory) ... ERROR
  ERROR: Failure: ImportError (libgsl.so.23: cannot open shared object file: No such file or directory)
    File "/usr/lib/python3.7/site-packages/nose/failure.py", line 39, in runTest
  ImportError: libgsl.so.23: cannot open shared object file: No such file or directory
  ERROR: Failure: ImportError (libgsl.so.23: cannot open shared object file: No such file or directory)
    File "/usr/lib/python3.7/site-packages/nose/failure.py", line 39, in runTest
  ImportError: libgsl.so.23: cannot open shared object file: No such file or directory
  FAILED (errors=2)
  PyNEST tests: 2
     Passed: 0
     Skipped: 0
     Failed: 2
--2-- Concerning GLS log :
Use GSL             : Yes (GSL 2.6)
    Includes        : /usr/include
    Libraries       : /usr/lib/libgsl.so;/usr/lib/libgslcblas.so