Added build dir, and gitignore

Makefile

@@ -1,14 +1,17 @@
-SHELL  := /bin/bash
-CC     := cc
-CFLAGS := -Wall -O2
-TARGET := fa2json
-SRCS   := fs-watcher.c json-writer.c
+SHELL		:= /bin/bash
+CC			:= cc
+MKDIR		:= mkdir
+CFLAGS		:= -Wall -Werror -Os
+BUILD_DIR	:= build
+TARGET		:= $(BUILD_DIR)/fa2json
+SRCS		:= fs-watcher.c json-writer.c
 
 .PHONY: all test dev clean
 
 all: $(TARGET)
 
 $(TARGET): $(SRCS)
+	$(MKDIR) -p $(BUILD_DIR)
 	$(CC) $(CFLAGS) -o $@ $^
 
 test: $(TARGET)
@@ -18,4 +21,4 @@ dev: $(TARGET)
 	node test/dev.mjs $(ARGS)
 
 clean:
-	rm -f $(TARGET)
+	rm -rf $(BUILD_DIR)