Makefile: add git function

Makefile

@@ -1,7 +1,20 @@
-include nemu/scripts/git.mk
+STUID = 211220000
+STUNAME = 张三
 
-default:
-	@echo "Please run 'make' under any subprojects to compile."
+# DO NOT modify the following code!!!
+
+GITFLAGS = -q --author='tracer-ics2022 <tracer@njuics.org>' --no-verify --allow-empty
+
+# prototype: git_commit(msg)
+define git_commit
+	-@git add $(NEMU_HOME)/.. -A --ignore-errors
+	-@while (test -e .git/index.lock); do sleep 0.1; done
+	-@(echo "> $(1)" && echo $(STUID) $(STUNAME) && uname -a && uptime) | git commit -F - $(GITFLAGS)
+	-@sync
+endef
+
+_default:
+	@echo "Please run 'make' under subprojects."
 
 submit:
 	git gc