I’ve completely reinstalled my OS and am now encountering issues that I’ve heard other talk about, I’ve followed the instructions on the website word by word, except that I forked Michael’s repo and changed to kwant version 1.0.3. This has worked before for me.



This is the error message:
brew install kwant
==> Installing kwant from basnijholt/homebrew-kwant
==> Using Homebrew-provided fortran compiler.
This may be changed by setting the FC environment variable.
==> Building with an alternative Fortran compiler
This is unsupported.
Warning: No Fortran optimization information was provided.  You may want to consider
setting FCFLAGS and FFLAGS or pass the `--default-fortran-flags` option to
`brew install` if your compiler is compatible with GCC.

If you like the default optimization level of your compiler, ignore this
warning.
==> Downloading pypi.python.org/packages/source/k/kwant/kwant-1.0.3.tar.gz
Already downloaded: /Library/Caches/Homebrew/kwant-1.0.3.tar.gz
==> Patching
patching file build.conf
==> python setup.py install --prefix=/usr/local/Cellar/kwant/1.0.3
Build configuration was:
User-configured LAPACK and BLAS
User-configured MUMPS
**********************************************************************
error: command 'clang' failed with exit status 1

READ THIS: https://git.io/brew-troubleshooting
If reporting this issue please do so at (not Homebrew/homebrew):
  https://github.com/basnijholt/homebrew-kwant/issues



Best Bas