Add Makefile for consistency with other suckless projects

Makefile

@@ -0,0 +1,25 @@
+# See LICENSE file for copyright and license details.
+
+include config.mk
+
+all: ${NAME}
+
+${NAME}:
+	@echo cargo build --release
+	@cargo build --release
+
+clean:
+	@echo cleaning
+	@cargo clean
+
+install: all
+	@echo installing executable file to ${DESTDIR}${PREFIX}/bin
+	@mkdir -p ${DESTDIR}${PREFIX}/bin
+	@cp -f target/release/${NAME} ${DESTDIR}${PREFIX}/bin
+	@chmod 755 ${DESTDIR}${PREFIX}/bin/${NAME}
+
+uninstall:
+	@echo removing executable file from ${DESTDIR}${PREFIX}/bin
+	@rm -f ${DESTDIR}${PREFIX}/bin/${NAME}
+
+.PHONY: all clean install uninstall

config.mk

@@ -0,0 +1,2 @@
+NAME = rwmstatus
+PREFIX = /usr/local