Just because....or maybe especially because it runs in Linux, it doesnot necessarily run on OSX
looking for crt0.o
sounds like an Xwindows thing,
or it is a c runtime???
whatever... maybe a clue to what the mystery program is and a link pointing to the source would be helpful to anyone seriously trying to help you.
the reference in the Makefile is enough
and the functions in the other source files are depending on that object to be available.