add Makefile to automate build process

Makefile

@@ -0,0 +1,20 @@
+CFLAGS=-O3 -Iinc/
+
+build: main
+
+out/:
+	mkdir out/
+
+main: out/main.o out/swapper.o
+	gcc $(CFLAGS) out/main.o out/swapper.o -o main
+
+out/main.o: out/ src/main.c
+	gcc $(CFLAGS) -c src/main.c -o out/main.o
+
+out/swapper.o: out/ src/swapper.c
+	gcc $(CFLAGS) -c src/swapper.c -o out/swapper.o
+
+clean:
+	rm -r main out/
+
+.PHONY: build clean