Rewrite Makefile

The Makefile was rewritten in a more usual fashion, using make variables
and prerequisites in the expected manner. The install destination was
changed from /bin to the more typical /usr/local/bin.

When this program is packaged, this destination should be changed to
/usr/bin, since packaged programs are usually meant to be in this
directory, they could be overwritten with a call such as:
make PREFIX=/usr install

Makefile

@@ -1,11 +1,22 @@
-all:
-	gcc -lm fetchy.c -o /bin/fetchy
+PREFIX = /usr/local
+
+CC = gcc
+CFLAGS = -lm
+
+all: fetchy
+
+fetchy:
+	$(CC) $(CFLAGS) fetchy.c -o $@
 
 clean:
-	rm fetchy
+	-rm -f fetchy
 
-install:
-	gcc -lm fetchy.c -o /bin/fetchy
+install: all
+	mkdir -p $(PREFIX)/bin
+	cp -f fetchy $(PREFIX)/bin
+	chmod 755 $(PREFIX)/bin/fetchy
 
 uninstall:
-	rm /bin/fetchy
+	-rm -f $(PREFIX)/bin/fetchy
+
+.PHONY: all install uninstall clean