Makefiles: Honour WIRINGPI_SUDO=0

This makes it possible for the caller of ./build to suppress the
chown/chmod of the gpio utility.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

gpio/Makefile

@@ -73,8 +73,10 @@ tags:	$(SRC)
 install: gpio
 	$Q echo "[Install]"
 	$Q cp gpio		$(DESTDIR)$(PREFIX)/bin
+ifneq ($(WIRINGPI_SUID),0)
 	$Q chown root.root	$(DESTDIR)$(PREFIX)/bin/gpio
 	$Q chmod 4755		$(DESTDIR)$(PREFIX)/bin/gpio
+endif
 	$Q mkdir -p		$(DESTDIR)$(PREFIX)/man/man1
 	$Q cp gpio.1		$(DESTDIR)$(PREFIX)/man/man1