来源：https://stackoverflow.com/questions/9052792/how-can-i-pass-a-macro-definition-from-make-command-line-arguments-d-to-c-s

命令：make CFLAGS=-Dvar=42

在 Makefile 内部使用 CFLAGS

CFLAGS+=$(CFLAGS)

添加定义

来源：https://cmake.org/cmake/help/latest/command/add_definitions.html

ADD_DEFINITIONS(-DENAGLE_EASYLOG)