Add GTK+ example

gtk/Makefile

@@ -0,0 +1,14 @@
+PACKAGE = helloworld
+OBJECTS = helloworld.o
+CFLAGS  = `pkg-config --cflags gtk+-3.0`
+LDADD   = `pkg-config --libs gtk+-3.0`
+
+helloworld: $(OBJECTS)
+	${CC} -o ${PACKAGE} ${OBJECTS} ${LDADD}
+
+.c.o:
+	${CC} ${CFLAGS} -c $<
+
+
+clean:
+	rm -f helloworld *.o