This define is only used by newlib internally, so stop exporting it
as HAVE_INITFINI_ARRAY since this can conflict with defines packages
use themselves.
We don't really need to add _ to HAVE_INIT_FINI too since it isn't
exported in newlib.h, but might as well be consistent here.
We can't (easily) add this to newlib_cflags like HAVE_INIT_FINI is
because this is based on a compile-time test in the top configure,
not on plain shell code in configure.host. We'd have to replicate
the test in every subdir in order to have it passed down.
437c5c5085