- in 1906, we changed the handling of compiler flags to include the
  exact values as used by OpenFOAM.

  While this is needed for compiling some external programs -- see
  OpenFOAM-plus#1256
  for the discussion -- it appears to bring in flags that upset
  some of the ParaView (and possibly VTK) compilation.

  The culprits are likely to be found in the various '-W' switches,
  but for now we simply extract a mininal set of compiler flags
  that include -std=c++11 -m64 -fPIC, but no optimization flags,
  additional warnings flags or OpenFOAM-specific defines.