> That's because it's in <sys/types.h>, which no ANSI C program will
> ever include, so there's no need to protect ANSI C programs from it.

Will ever include _directly_.  Are you certain none of the
ANSI-specified headers end up pulling it in?  For example, it looks as
though <stdlib.h> will unless you have _ANSI_SOURCE, _POSIX_C_SOURCE,
or _XOPEN_SOURCE defined - does -ansi define _ANSI_SOURCE?

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