问题
I have an Xcode project, which has a subproject which is a static library. I've defined a preprocessor macro in the parent project (in Build Settings), and I want it to be recognized by the subproject at compile time (I have some #ifdef statements in the subproject). But the macro is always undefined in the subproject, no matter what I do. Is it possible to do what I want?
来源：https://stackoverflow.com/questions/21470300/preprocessor-macro-in-parent-project-for-use-in-subproject