I was trying to pip install PyCrypto in a PyPy virtualenv and kept getting build errors, mostly related to PyLongObject.

I worked around the problem by uninstalling the gmp library.

I’m on OS X so I did:

brew uninstall gmp

(If you’re on a different platform, replace “brew” with your package manager — apt-get, yum, etc.)

Then things worked:

(pypy-pycrypto)marca@marca-mac:~/python/virtualenvs$ pip install PyCrypto
Downloading/unpacking PyCrypto
  Real name of requirement PyCrypto is pycrypto
  Using download cache from /Users/marca/.pip/download-cache/https%3A%2F%2Fpypi.python.org%2Fpackages%2Fsource%2Fp%2Fpycrypto%2Fpycrypto-2.6.1.tar.gz
  Running setup.py egg_info for package PyCrypto

Installing collected packages: PyCrypto
...
Successfully installed PyCrypto
Cleaning up...

Voila!