Description
The current CMakeLists.txt does not account for Snappy include folders causing the compilation to fail when a custom snappy location is provided using -DSNAPPY_ROOT_DIR
e.g .
cmake avro-c-1.7.7 -DSNAPPY_ROOT_DIR=${SNAPPY_INSTALL_DIR}
In https://github.com/apache/avro/blob/release-1.7.7/lang/c/CMakeLists.txt#L143 we should include
include_directories(${SNAPPY_INCLUDE_DIR})