Rework immutability and overlays

overlayfs-tools/makefile

@@ -0,0 +1,23 @@
+CC = gcc
+CFLAGS = -Wall -std=c99
+LDFLAGS = -lm
+ifneq (,$(wildcard /etc/alpine-release))
+  LDFLAGS += -lfts
+endif
+
+all: overlayfs-tools
+
+overlayfs-tools: main.o logic.o sh.o
+	$(CC) main.o logic.o sh.o -o overlayfs-tools $(LDFLAGS)
+
+main.o: main.c logic.h
+	$(CC) $(CFLAGS) -c main.c
+
+logic.o: logic.c logic.h sh.h
+	$(CC) $(CFLAGS) -c logic.c
+
+sh.o: sh.c sh.h
+	$(CC) $(CFLAGS) -c sh.c
+
+clean:
+	$(RM) main.o logic.o sh.o overlayfs-tools