Initial commit for bscpkgs in Huawei cluster

- Use python 3.9 because it is cached in aarch64

- Pass some parameters to wrapCCWith to use our cpu flags and gcc-toolchain
  Also remove some unnecessary extraBuildCommans since they are already
  done

- Add a patch from nixpkgs's clang to avoid unallowed accesess to /usr

  We found that in nix-shell clang was accessing /usr/include in the following test

  \#include <cmath>
  int main(int argc, char *argv[]) {
      return pow((double)argc, (double)77.4);
  }

  This was replacing pow by __pow_finite, which is the one used
  in the glibc of the system (MN4, CTE-Huawei). We end up linking
  with our glibc from nix, which does not implement it (only the
  versioned info is available)

  I add the reference of the nixpkgs repository
  https://github.com/NixOS/nixpkgs/issues/151879

- Update paraver
- Add explicitly flags in extrae to enable OpenMP. Useful for Huawei