Also, I prefer adding -MMD to CFLAGS instead of having an additional rule for dependency generation: This way, you won't unnecessarily trigger dependency generation on targets which do not build objects like clean.
Actually, in this case, I believe LDLIBS would be more appropriate since the OP isn't passing any flags to `ld` but rather the libraries for `ld` to link. I ended up getting hit be this in a simple Makefile a few weeks ago that worked in Fedora but failed in Ubuntu.
The target was "%.o: %.c", which make auto-expands to be (something like):
$(CC) $(CFLAGS) $(LDFLAGS) $@ $^ $(LDLIBS)
EDIT: stop editing your answer while I'm writing my own ;)
According to the manual, the built-in rule for linking an executable `n` from a single object file is
$(CC) $(LDFLAGS) n.o $(LOADLIBES) $(LDLIBS)