On some platforms, the system headers expose different interfaces depending
on what macros are defined, for example to provide different standards
compliance level. Create a common place where we can declare such macros,
so that our code can behave in the same way when it's in different files.
Individual .c files can still override these requirements by defining
macros before including the common header, if it's really necessary.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
3a98885950