fusl/arch/i386/bits/stdarg.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))

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