Johannes Sixt writes:

quoted text
> This is just too ugly to be included...
>
> die_nicely() uses the variable argument list twice. The recent fix for
> this in 7e5dcea8311 uses va_copy. However, on older systems this function
> is not available. This fix assumes that those systems that do have
> the function actually implement it as macro, and we use it to remove
> the entire nicely() functionality.
>
> Since va_copy() must be provided by the compiler, we don't have a
> reasonable chance to provide a working definition in git_compat_util.h.

Some older (pre-C99) versions of gcc name it __va_copy() instead.  Is
there any guarantee that va_copy() will be a macro on systems that
provide it?  If neither va_copy() nor __va_copy() are available,
memcpy(&(DEST), &(SRC), sizeof(DEST)) should work for any va_list
type.  It's what I use on one project:

#ifdef HAVE_VA_COPY
#define VA_COPY(DEST, SRC) va_copy(DEST, SRC)
#elif HAVE___VA_COPY
#define VA_COPY(DEST, SRC) __va_copy(DEST, SRC)
#else
#define VA_COPY(DEST, SRC) memcpy(&(DEST), &(SRC), sizeof(DEST))
#endif

with appropriate autoconf tests, basically two copies of this:

dnl How to copy one va_list to another?
AC_CACHE_CHECK([for va_copy], ac_cv_c_va_copy, [AC_LINK_IFELSE(
  [AC_LANG_PROGRAM([#include <stdarg.h>], [va_list ap1, ap2; va_copy(ap1, ap2);])],
  [ac_cv_c_va_copy="yes"],
  [ac_cv_c_va_copy="no"]
)])
if test "$ac_cv_c_va_copy" = "yes" ; then
  AC_DEFINE(HAVE_VA_COPY, 1, [Define if we have va_copy])
fi

I'm not sure how to translate the tests to git's coding style most
easily.

Michael Poole
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