I'm running NetBSD-4 with modified cdefs.h
and pcc fails like this.
But I don't see any changes related to pcc in HEAD's stdarg.h.
Any comments?

0 ~> cat main.c         
#include <stdarg.h>
#include <stdio.h>

void my_log (const char *format, ... )
{
   va_list ap;

   va_start (ap, format);
   vprintf (format, ap);
   va_end (ap);
}

int main ()
{
   my_log ("Hello World!\n");
   return 0;
}
0 ~> gcc -o main main.c && ./main
Hello World!
0 ~> pcc -o main main.c && ./main 
main.o: In function `my_log':
: undefined reference to `__builtin_next_arg'
1 ~>

-- 
Best regards, Aleksey Cheusov.