Troubleshooting installation issues

Sometimes, things go south.

When installing the development sandbox by typing:

make virtualenv-dev

Building wheels for collected packages: pycrypto:

src/_fastmath.c:36:11: fatal error: 'gmp.h' file not found
# include <gmp.h>
          ^~~~~~~
197 warnings and 1 error generated.

Solution:

export CPPFLAGS=-I/usr/local/opt/gmp/include
export LDFLAGS=-L/usr/local/opt/gmp/lib
make virtualenv-dev