You'll need to add #include <functional> and #include <unordered_map> at the top (under #include "list.h"). [In hash.h]
You'll also need to add the flag:
-std=c++11
..to g++ in the makefile:
CXXFLAGS+= -I. -DUSE_REUSABLES -DUSE_GMP -DUNIXVER -DUSE_BUILTIN_FCREATE -std=c++11