The structure of the va_list type is architecture-dependent, and it
doesn't seem possible to initialize va_list variables in a portable way
(except by using va_start()). In particular, the x86_64 ABI defines the
type like this:
typedef struct {
unsigned int gp_offset;
unsigned int fp_offset;
void *overflow_arg_area;
void *reg_save_area;
} va_list[1];
Fortunately, the va_start() macro expects an uninitialized va_list
variable, so we can simply remove the initializers to make the code
portable.
Signed-off-by: Jakob Olesen <jolesen@fb.com>