Build for Summit TensorFlow Dockerfile.python3 fails

[markcoletti]

When attempting to build Dockerfile.python3 on Summit, I get the following errors:

    building '_cffi_backend' extension
    creating build/temp.linux-ppc64le-3.4
    creating build/temp.linux-ppc64le-3.4/c
    gcc -pthread -Wno-unused-result -DDYNAMIC_ANNOTATIONS_ENABLED=1 -DNDEBUG -O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector-strong --param=ssp-buffer-size=4 -grecord-gcc-switches -m64 -mcpu=power8 -mtune=power8 -D_GNU_SOURCE -fPIC -fwrapv -fPIC -DUSE__THREAD -DHAVE_SYNC_SYNCHRONIZE -I/usr/include/ffi -I/usr/include/libffi -I/usr/include/python3.4m -c c/_cffi_backend.c -o build/temp.linux-ppc64le-3.4/c/_cffi_backend.o
    c/_cffi_backend.c:15:17: fatal error: ffi.h: No such file or directory
     #include <ffi.h>
                     ^
    compilation terminated.
    error: command 'gcc' failed with exit status 1

    ----------------------------------------
Command "/usr/bin/python3.4 -u -c "import setuptools, tokenize;__file__='/tmp/pip-install-1n_fkums/cffi/setup.py';f=getattr(tokenize, 'open', open)(__file__);code=f.read().replace('\r\n', '\n');f.close();exec(compile(code, __file__, 'exec'))" install --record /tmp/pip-record-cvou3obo/install-record.txt --single-version-externally-managed --compile" failed with error code 1 in /tmp/pip-install-1n_fkums/cffi/
The command '/bin/sh -c ln -s /usr/local/cuda/lib64/stubs/libcuda.so /usr/local/cuda/lib64/stubs/libcuda.so.1 &&     ldconfig /usr/local/cuda/lib64/stubs &&     pip3 install horovod &&     ldconfig' returned a non-zero code: 1
Build Failed
[INFO] Finished streaming build
[ERROR] Container Builder exception encountered: Build failed with exit code 1

I suspect there is a missing dependency.