feat: add Makefile for building and testing

Co-authored-by: aider (deepseek/deepseek-coder) <aider@aider.chat>

Makefile

@@ -0,0 +1,25 @@
+CC = gcc
+CFLAGS = -Wall -Wextra -g
+LDFLAGS = -ljack -lm
+
+TARGET = jack-looper
+TEST_TARGET = test_engine
+
+SRCS = engine.c main.c
+TEST_SRCS = test_engine.c engine.c
+
+all: $(TARGET)
+
+$(TARGET): $(SRCS)
+	$(CC) $(CFLAGS) -o $@ $^ $(LDFLAGS)
+
+test: $(TEST_TARGET)
+	./$(TEST_TARGET)
+
+$(TEST_TARGET): $(TEST_SRCS)
+	$(CC) $(CFLAGS) -o $@ $^ $(LDFLAGS)
+
+clean:
+	rm -f $(TARGET) $(TEST_TARGET)
+
+.PHONY: all test clean