reftable/stack: fix compiler warning due to missing braces

While perfectly legal, older compiler toolchains complain when
zero-initializing structs that contain nested structs with `{0}`:

    /home/libgit2/source/deps/reftable/stack.c:862:35: error: suggest braces around initialization of subobject [-Werror,-Wmissing-braces]
            struct reftable_addition empty = REFTABLE_ADDITION_INIT;
                                             ^~~~~~~~~~~~~~~~~~~~~~
    /home/libgit2/source/deps/reftable/stack.c:707:33: note: expanded from macro 'REFTABLE_ADDITION_INIT'
    #define REFTABLE_ADDITION_INIT {0}
                                    ^

We had the discussion around whether or not we want to handle such bogus
compiler errors in the past already [1]. Back then we basically decided
that we do not care about such old-and-buggy compilers, so while we
could fix the issue by using `{{0}}` instead this is not the preferred
way to handle this in the Git codebase.

We have an easier fix though: we can just drop the macro altogether and
handle initialization of the struct in `reftable_stack_addition_init()`.
Callers are expected to call this function already, so this change even
simplifies the calling convention.

[1]: https://lore.kernel.org/git/20220710081135.74964-1-sunshine@sunshineco.com/T/

Suggested-by: Carlo Arenas <carenas@gmail.com>
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

0 files changed, 0 insertions, 0 deletions