Crt1.o error

hi
iam trying to work with graphics using gcc in freebsd system.so i installed sdl,sdl image,libgraph.When i give make command in libgraph folder it says undefined reference to crt1.o.I think it is due to there is not main in the crt1.c but extern main (); is declared.I can use gcc -c but how to edit makefile or any other ideas?
help me