Add reinstall option, which doesn't clobber config file

Author: dlenski

Makefile

@@ -5,15 +5,26 @@ BINDIR=$(PREFIX)/bin
 all:
 	@echo "Run 'make install' for installation."
 	@echo "Run 'make uninstall' for uninstallation."
+	@echo "Run 'make reinstall' for installation without clobbering existing config file."
 
-install:
+install-noconf:
 	install -Dm755 create_ap $(DESTDIR)$(BINDIR)/create_ap
-	install -Dm644 --backup=existing --suffix=.orig create_ap.conf $(DESTDIR)/etc/create_ap.conf
 	[ ! -d /lib/systemd/system ] || install -Dm644 create_ap.service $(DESTDIR)$(PREFIX)/lib/systemd/system/create_ap.service
 	[ ! -e /sbin/openrc-run ] || install -Dm755 create_ap.openrc $(DESTDIR)/etc/init.d/create_ap
 	install -Dm644 bash_completion $(DESTDIR)$(PREFIX)/share/bash-completion/completions/create_ap
 	install -Dm644 README.md $(DESTDIR)$(PREFIX)/share/doc/create_ap/README.md
 
+install: install-noconf
+	[ -e $(DESTDIR)/etc/create_ap.conf ] && echo "Existing $(DESTDIR)/etc/create_ap.conf will be renamed with .orig suffix" >&2
+	install -Dm644 --backup=existing --suffix=.orig create_ap.conf $(DESTDIR)/etc/create_ap.conf
+
+reinstall: install-noconf
+	if [ -e $(DESTDIR)/etc/create_ap.conf ]; then \
+	    echo "Leaving existing $(DESTDIR)/etc/create_ap.conf unchanged" >&2; \
+	else \
+	    install -Dm644 --backup=existing --suffix=.orig create_ap.conf $(DESTDIR)/etc/create_ap.conf; \
+	fi
+
 uninstall:
 	rm -f $(DESTDIR)$(BINDIR)/create_ap
 	rm -f $(DESTDIR)/etc/create_ap.conf