problem with python-snappy installation on a virtualenv

I tried to install python-snappy on a virtualenv with python 2.7. It failed

` x86_64-linux-gnu-gcc -pthread -DNDEBUG -g -fwrapv -O2 -Wall -Wstrict-prototypes -fno-strict-aliasing -Wdate-time -D_FORTIFY_SOURCE=2 -g -fstack-protector-strong -Wformat -Werror=format-security -fPIC -I/usr/include/python2.7 -c snappy/snappymodule.cc -o build/temp.linux-x86_64-2.7/snappy/snappymodule.o
cc1plus: warning: command line option ‘-Wstrict-prototypes’ is valid for C/ObjC but not for C++
snappy/snappymodule.cc:31:22: fatal error: snappy-c.h: Aucun fichier ou dossier de ce type
compilation terminated.
error: command 'x86_64-linux-gnu-gcc' failed with exit status 1

----------------------------------------
Failed building wheel for python-snappy
Running setup.py clean for python-snappy
Successfully built cyvcf2 peddy
Failed to build python-snappy
Installing collected packages: sqlalchemy, numpy, cyvcf2, peddy, geneimpacts, python-snappy
Running setup.py install for geneimpacts ... done
Running setup.py install for python-snappy ... error
Complete output from command /home/aurelien.beliard/.virtualenvs/varapp/bin/python -u -c "import setuptools, tokenize;__file__='/tmp/pip-build-1c10wm/python-snappy/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-CzAHUl-record/install-record.txt --single-version-externally-managed --compile --install-headers /home/aurelien.beliard/.virtualenvs/varapp/include/site/python2.7/python-snappy:
/usr/lib/python2.7/distutils/dist.py:267: UserWarning: Unknown distribution option: 'cffi_modules'
warnings.warn(msg)
running install
running build
running build_py
creating build
creating build/lib.linux-x86_64-2.7
creating build/lib.linux-x86_64-2.7/snappy
copying snappy/__init__.py -> build/lib.linux-x86_64-2.7/snappy
copying snappy/snappy_cffi.py -> build/lib.linux-x86_64-2.7/snappy
copying snappy/snappy.py -> build/lib.linux-x86_64-2.7/snappy
copying snappy/snappy_cffi_builder.py -> build/lib.linux-x86_64-2.7/snappy
copying snappy/__main__.py -> build/lib.linux-x86_64-2.7/snappy
copying snappy/snappy_formats.py -> build/lib.linux-x86_64-2.7/snappy
copying snappy/hadoop_snappy.py -> build/lib.linux-x86_64-2.7/snappy
running build_ext
building 'snappy._snappy' extension
creating build/temp.linux-x86_64-2.7
creating build/temp.linux-x86_64-2.7/snappy
x86_64-linux-gnu-gcc -pthread -DNDEBUG -g -fwrapv -O2 -Wall -Wstrict-prototypes -fno-strict-aliasing -Wdate-time -D_FORTIFY_SOURCE=2 -g -fstack-protector-strong -Wformat -Werror=format-security -fPIC -I/usr/include/python2.7 -c snappy/snappymodule.cc -o build/temp.linux-x86_64-2.7/snappy/snappymodule.o
cc1plus: warning: command line option ‘-Wstrict-prototypes’ is valid for C/ObjC but not for C++
snappy/snappymodule.cc:31:22: fatal error: snappy-c.h: Aucun fichier ou dossier de ce type
compilation terminated.
error: command 'x86_64-linux-gnu-gcc' failed with exit status 1
`

I tried to reinstall libsnappy-dev to correct it, but i have another problem
I tried to install cffi but there already is a problem:

```
static struct module_state _state;
^
x86_64-linux-gnu-gcc -pthread -DNDEBUG -g -fwrapv -O2 -Wall -Wstrict-prototypes -fno-strict-aliasing -Wdate-time -D_FORTIFY_SOURCE=2 -g -fstack-protector-strong -Wformat -Werror=format-security -fPIC -I/usr/include/python2.7 -c snappy/crc32c.c -o build/temp.linux-x86_64-2.7/snappy/crc32c.o
c++ -pthread -shared -Wl,-O1 -Wl,-Bsymbolic-functions -Wl,-Bsymbolic-functions -Wl,-z,relro -fno-strict-aliasing -DNDEBUG -g -fwrapv -O2 -Wall -Wstrict-prototypes -Wdate-time -D_FORTIFY_SOURCE=2 -g -fstack-protector-strong -Wformat -Werror=format-security -Wl,-Bsymbolic-functions -Wl,-z,relro -Wdate-time -D_FORTIFY_SOURCE=2 -g -fstack-protector-strong -Wformat -Werror=format-security build/temp.linux-x86_64-2.7/snappy/snappymodule.o build/temp.linux-x86_64-2.7/snappy/crc32c.o -lsnappy -o build/lib.linux-x86_64-2.7/snappy/_snappy.so
c++: error: unrecognized command line option ‘-Wdate-time’
c++: error: unrecognized command line option ‘-fstack-protector-strong’
c++: error: unrecognized command line option ‘-Wdate-time’
c++: error: unrecognized command line option ‘-fstack-protector-strong’
error: command 'c++' failed with exit status 1
```

Start by reproducing installation in the Python 2.7 virtualenv and inspect setup.py, snappy/snappymodule.cc, and snappy/crc32c.c alongside the reported header and compiler errors. Determine whether the failure is project packaging or environment-specific; done means the supported installation path succeeds or the required environment and limitation are documented.

索引モデルが issue の本文から書いたものです。