Merge branch 'master' into man-page

Makefile

-PREFIX=$(DESTDIR)/usr
-BINDIR=$(PREFIX)/bin
-MANDIR=$(PREFIX)/share/man/man1
+ifeq ($(PREFIX),)
+	PREFIX := /usr
+endif
+BINDIR=$(DESTDIR)$(PREFIX)/bin
+MANDIR=$(DESTDIR)$(PREFIX)/share/man/man1
 
 CC=gcc
 CFLAGS=-std=c89 -O2 -pedantic -Wall -I"./include" -D_XOPEN_SOURCE=500
 	$(CC) $(CFLAGS) -g -o $@ $^
 
 install: light
-	mkdir -p $(BINDIR)
-	cp -f ./light $(BINDIR)/light
-	chown root $(BINDIR)/light
-	chmod 4755 $(BINDIR)/light
-	mkdir -p $(MANDIR)
-	cp -f light.1 $(MANDIR)
+	install -dZ $(BINDIR)
+	install -DZ -m 4755 ./light -t $(BINDIR)
+	install -dZ $(MANDIR)
+	install -DZ light.1 -t $(MANDIR)
 
 uninstall:
-	rm $(BINDIR)/light
+	rm -f $(BINDIR)/light
 	rm -rf /etc/light
-	rm $(MANDIR)/light.1.gz
+	rm -f $(MANDIR)/light.1.gz
 
 clean:
 	rm -vfr *~ light light.1.gz

README.md

 
 ### Manual
 
-`make && make install`
+`make && sudo make install`
 
 **Optional:** If you want to use udev rules instead of suid to manage sysfs permissions, you may skip the `make install` step and instead add something like the following to `/etc/udev/rules.d/90-backlight.rules` after copying your binaries:
 ```