I was checking the library to check what was happening and I found out that in sha1.cpp, it makes calls to avr/io.h, avr/pgmspace.h.
Those libraries are AVR exclusive, which means that they depend on the AVR architecture. Since the Galileo uses an x86 architecture, this library is not compatible with it.
In order to make the library work with the Galileo, it'd require major modifications. I believe an easier approach for this issue is for you to write your own library based on Cathedrow/Cryptosuite, but making it compatible with the Galileo's architecture.