An equivalent of the Ubuntu libsnappy-dev package is simply snappy, you can install it like this:
brew install snappy
Optionally, you might need to add links to the libraries in /usr/local/lib so other packages can link to it:
cd /usr/local/lib/
ln -s /usr/local/Cellar/snappy/1.1.1/lib/libsnappy.1.dylib
ln -s /usr/local/Cellar/snappy/1.1.1/lib/libsnappy.a
ln -s /usr/local/Cellar/snappy/1.1.1/lib/libsnappy.dylib