Mine

all: program1

# Compiler
CC=gcc
# Where to install
INSTDIR = /usr/local/bin
# Where include files are kept
VPATH = src
# Compile options
CFLAGS = -Wall -g

program1: main.o a_functions.o b_functions.o c_functions.o d_functions.o
	$(CC) -o program1 main.o a_functions.o b_functions.o c_functions.o d_functions.o
main.o: main.c main.h
a_functions.o: a_functions.c a.h
b_functions.o: b_functions.c b.h
c_functions.o: c_functions.c c.h
d_functions.o: d_functions.c d.h

clean:
	-rm main.o a_functions.o b_functions.o c_functions.o d_functions.o program1 

install: program1
	@if [ -d $(INSTDIR) ]; \
		then \
		cp program1 $(INSTDIR) && \
		chmod a+x $(INSTDIR)/program1 && \
		chmod og-w $(INSTDIR)/program1 && \
		echo "Installed in $(INSTDIR)"; \
	else \
		echo "Sorry, $(INSTDIR) does not exist"; \
	fi

uninstall:
	@if [ -e $(INSTDIR)/program1 ]; \
		then \
		rm $(INSTDIR)/program1 && \
		echo "Removed program from $(INSTDIR)"; \
	else \
		echo "Program not found in $(INSTDIR)"; \
	fi