Error installing bcrypt with pip on OS X: can't find ffi.h (libffi is installed)

Question

I\'m getting this error when trying to install bcrypt with pip. I have libffi installed in a couple places (the Xcode OS X SDK, and from homebrew), but I don\'t know how to

Answer 1

Xcode was already installed for me (as mentioned in the question itself that it does provide the ffi.h header), but for some reason that didn't populate /usr/include (as Zachary Young mentioned). I dug around to see why the /usr/include wasn't populated and found that the following command fixed it:

$ xcode-select --install

Missing /usr/include after Yosemite and Xcode install?