makefile: Add install and uninstall targets.

Makefile

 CFLAGS+=	`pkg-config --cflags fuse`
 LIBS+=		`pkg-config --libs fuse`
 
+PREFIX ?= /usr/local
+
+INSTALL_PRG = fjfs
+INSTALL_PRG_DIR = $(subst //,/,$(DESTDIR)/$(PREFIX)/bin)
+
+.PHONY: distclean clean install uninstall
+
 all: fjfs
 
 fjfs: fjfs.c
 
 clean:
 	rm -f fjfs
+
+distclean: clean
+
+install: all
+	install -d "$(INSTALL_PRG_DIR)"
+	install $(INSTALL_PRG) "$(INSTALL_PRG_DIR)"
+
+uninstall:
+	rm $(INSTALL_PRG_DIR)/$(INSTALL_PRG)