added Makefile to c library

lib/c/Makefile

+liblabcomm.a : labcomm.o labcomm_fd_reader_writer.o
+	ar -r liblabcomm.a labcomm.o labcomm_fd_reader_writer.o
+
+labcomm.o : labcomm.c labcomm.h  labcomm_private.h
+	gcc -c labcomm.c
+
+labcomm_fd_reader_writer.o : labcomm_fd_reader_writer.c  labcomm_fd_reader_writer.h  labcomm.h  labcomm_private.h
+	gcc -c labcomm_fd_reader_writer.c
+
+clean:
+	rm *.o
+
+distclean: clean
+	rm liblabcomm.a