Create LCD driver

Makefile

@@ -2,15 +2,20 @@ CC=clang
 CFLAGS=-std=c99
 LD=clang
 LDFLAGS=-lgpio
-OBJS=main.o lcd.o
+OBJS=main.o util.o lcd.o
+OUTFILE=rpi4b-temp-humidity
+
+${OUTFILE}: ${OBJS}
+	${LD} ${LDFLAGS} -o $@ ${OBJS}
 
 main.o lcd.o: lcd.h
-
-rpi4b-temp-himidity: ${OBJS}
-	${LD} ${LDFLAGS} -o $@ ${OBJS}
+main.o util.o lcd.o: util.h
 
 .c.o:
 	${CC} ${CFLAGS} -c $<
 
+clean:
+	rm -f ${OUTFILE} ${OBJS}
+
 .SUFFIXES: .c .o
 .PHONY: clean