I am currently trying to install pycrypto and when I execute python setup.py build I receive this following error:
cc -bundle -undefined dynamic_lookup -arch
For those of you also looking to install pycrypto as well as the cryptography package, this is the command that ended up working for me:
env ARCHFLAGS="-arch x86_64" LDFLAGS="-L/usr/local/opt/openssl/lib" CFLAGS="-I/usr/local/opt/openssl/include" pip install cryptography