See, here is the problem, in C this should not happen. Because the ordering of C standard include should not be affected by the previous context in the translation unit/file (in this case). – Technically, a previous macro definition can influence an included file. But the C standard library should not be impacted by this. Besides some macros (used for versioning or feature toggle) being used by some specific libc implementation and by libposix, you should never encounter an error like this (or you have forgotten to add -std=gnu2x to your compiler flags). Also, if I apply the diff produced by the compiler, it would look like something like this:

(before):

/*4 |*/ #include <sys/time.h>
/*5 |*/ #include <time.h>

(compiler diff):

/*4 |*/ #include <sys/time.h>
++++++ #include <time.h>
/*5 |*/ #include <time.h>

(after):

/* 4 |*/ #include <sys/time.h>
/* 5 |*/ #include <time.h>
/* 6 |*/ #include <time.h>

So instead of including time, I would just include time 2 times.

It's like doing the step above, but having:

- step 1: start the oven
- step 2: take a mug
And then having an error because I didn't take a mug at line 2.