ref: 685670b0ddb9eb8398d88cbae1b08a2872b5adf6
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; }