Implementing Android.bp for generating shared library

Question

Consider the following files :

abc.c

#ifdef MY_FLAG
#include <stdio.h>

int main() {
    printf("hello world\n");
}
#endif

Android.bp

cc_defaults {
    name: "my_defaults_1",
    srcs: ["abc.c"],
}

cc_defaults {
    name:  "my_defaults_2",
    defaults: ["my_defaults_1"],
    cflags: ["-DMY_FLAG"],
}

cc_library_shared {
    name: "my_library",
    defaults: ["my_defaults_2"],
}

Here my question is, where do i need to define my flag(MY_FLAG) in order to get that file executed and getting print, is it in my_defaults_1 or my_defaults_2 or defining in any one of these, will cause same result? Because when i defined the flag in my_defaults_2 i didn't got the print.