Re: [PATCH] list-objects-filter-options: fix function name in BUG

> I actually wonder if it is time to drop HAVE_VARIADIC_MACROS completely.
> They are in C99, and we have been introducing many other C99-isms. It
> would be a minor cleanup to a few bits of code, which perhaps isn't
> worth the risk. But I also have a vague memory of not being able to
> implement some interfaces because we couldn't count on them.
>
> Poking around, 3689539127 (add helpers for allocating flex-array
> structs, 2016-02-22) points out one such case. I think discussion of
> BUG_ON() got blocked by that, too. Looks like we also discussed them in
> the big "C99 weather balloon" thread:
>
>   https://lore.kernel.org/git/20170710070342.txmlwwq6gvjkwtw7@sigill.intra.peff.net/
>
> Maybe it's time for something like this as a test:

> diff --git a/git-compat-util.h b/git-compat-util.h
> index 2fd9d5b403..fe5de2239f 100644
> --- a/git-compat-util.h
> +++ b/git-compat-util.h
> @@ -1194,14 +1194,9 @@ static inline int regexec_buf(const regex_t *preg, const char *buf, size_t size,
>  /* usage.c: only to be used for testing BUG() implementation (see test-tool) */
>  extern int BUG_exit_code;
>  
> -#ifdef HAVE_VARIADIC_MACROS
>  __attribute__((format (printf, 3, 4))) NORETURN
>  void BUG_fl(const char *file, int line, const char *fmt, ...);
>  #define BUG(...) BUG_fl(__FILE__, __LINE__, __VA_ARGS__)
> -#else
> -__attribute__((format (printf, 1, 2))) NORETURN
> -void BUG(const char *fmt, ...);
> -#endif
>  
>  /*
>   * Preserves errno, prints a message, but gives no warning for ENOENT.
> diff --git a/usage.c b/usage.c
> index 06665823a2..b72f48f70e 100644
> --- a/usage.c
> +++ b/usage.c
> @@ -273,23 +273,13 @@ static NORETURN void BUG_vfl(const char *file, int line, const char *fmt, va_lis
>  	abort();
>  }
>  
> -#ifdef HAVE_VARIADIC_MACROS
>  NORETURN void BUG_fl(const char *file, int line, const char *fmt, ...)
>  {
>  	va_list ap;
>  	va_start(ap, fmt);
>  	BUG_vfl(file, line, fmt, ap);
>  	va_end(ap);
>  }
> -#else
> -NORETURN void BUG(const char *fmt, ...)
> -{
> -	va_list ap;
> -	va_start(ap, fmt);
> -	BUG_vfl(NULL, 0, fmt, ap);
> -	va_end(ap);
> -}
> -#endif
>  
>  #ifdef SUPPRESS_ANNOTATED_LEAKS
>  void unleak_memory(const void *ptr, size_t len)