Makefile tweaks

Modified according to
[dwm](http://git.suckless.org/dwm/file/Makefile.html) 's
Makefile file.

Makefile

@@ -1,17 +1,31 @@
-PREFIX ?= /usr/local
-CC ?= cc
+PREFIX  ?= /usr/local
+CC      ?= cc
+CFLAGS  = -pedantic -Wall -Wno-deprecated-declarations -Os
 LDFLAGS = -lX11
 
-output: dwmblocks.c blocks.def.h blocks.h
-	${CC}  dwmblocks.c $(LDFLAGS) -o dwmblocks
+all: options dwmblocks
+
+options:
+	@echo dwmblocks build options:
+	@echo "CFLAGS  = ${CFLAGS}"
+	@echo "LDFLAGS = ${LDFLAGS}"
+	@echo "CC      = ${CC}"
+
+dwmblocks: dwmblocks.c blocks.def.h blocks.h
+	${CC} -o dwmblocks dwmblocks.c ${CFLAGS} ${LDFLAGS}
+
 blocks.h:
 	cp blocks.def.h $@
 
-
 clean:
-	rm -f *.o *.gch dwmblocks
-install: output
-	mkdir -p $(DESTDIR)$(PREFIX)/bin
-	install -m 0755 dwmblocks $(DESTDIR)$(PREFIX)/bin/dwmblocks
+	${RM} *.o *.gch dwmblocks
+
+install: dwmblocks
+	mkdir -p ${DESTDIR}${PREFIX}/bin
+	cp -f dwmblocks ${DESTDIR}${PREFIX}/bin
+	chmod 755 ${DESTDIR}${PREFIX}/bin/dwmblocks
+
 uninstall:
-	rm -f $(DESTDIR)$(PREFIX)/bin/dwmblocks
+	${RM} ${DESTDIR}${PREFIX}/bin/dwmblocks
+
+.PHONY: all options clean install uninstall