ref: d41b70b7628e913d8af6676c2a5be6ee2d68adf9
dir: /sys/src/ape/lib/ap/gen/memccpy.c/
#include <string.h>
void*
memccpy(void *a1, void *a2, int c, size_t n)
{
unsigned char *s1, *s2;
s1 = a1;
s2 = a2;
c &= 0xFF;
while(n > 0) {
if((*s1++ = *s2++) == c)
return s1;
n--;
}
return 0;
}