I have a VirtualEnv, and I wanted to install a Python package pyfftw in this case.
pip install pyfftw
But I can se some C compiler error, which was due to a .h file not being found.
I double checked I had the Development files (.C and .H) and I did.
It turns out that my Dev env does not look in my local area .... so to fix
export DYLD_LIBRARY_PATH=/usr/local/lib export LDFLAGS="-L/usr/local/lib" export CFLAGS="-I/usr/local/include"
Then in the same shell
pip install py
And all is working.