Make building projects not libraries

[nixpulvis]

We can currently build libraries that depend on AVRM and each other, but projects that link these all together and really only need a main.c file are a bit unsupported. I'm currently using the following Makefile for these kinds of projects:

AVRM = /usr/local/Cellar/avrm/0.0.5
DS1307 = /usr/local/Cellar/ds1307/0.0.3
MAX7221 = /usr/local/Cellar/max7221/0.0.3
DEPENDENCIES = $(DS1307) $(MAX7221) $(AVRM)
LDLIBS = -lds1307 -lmax7221 -lavrm

include $(AVRM)/Makefile

Which yields warnings, but still technically works for flashing, and sizing, etc. I'd just like make to not output the following:

find: lib: No such file or directory
find: test: No such file or directory
find: lib: No such file or directory
find: test: No such file or directory
make: *** No rule to make target `libavrm.a()', needed by `all'.  Stop.