musl/include/stdarg.h

#ifndef _STDARG_H
#define _STDARG_H

#ifdef __cplusplus
extern "C" {
#endif

#define __NEED_va_list

#include <bits/alltypes.h>

#define __VA_ALIGNED_SIZE(x) ((sizeof(x) + sizeof(int) - 1) & ~(sizeof(int) - 1))

#define va_start(ap, last) ((ap) = (void *)(((char *)&(last)) + __VA_ALIGNED_SIZE(last)))
#define va_end(ap) ((void)0)
#define va_copy(dest, src) ((dest) = (src))

#if 0
#define va_arg(ap, type) \
	( ((ap) = (va_list)((char *)(ap) + sizeof(type))), \
	*(type *)(void *)((char *)(ap) - sizeof(type)) )
#endif

#define va_arg(ap, type) \
	( ((ap) = (va_list)((char *)(ap) + __VA_ALIGNED_SIZE(type))), \
	*(type *)(void *)((char *)(ap) - __VA_ALIGNED_SIZE(type)) )

#ifdef __cplusplus
}
#endif

#endif