ref: bc7d74f09b53c39ada4e73ce73c01c6c0928f9f4
dir: /sys/src/ape/lib/ap/gen/strncat.c/
#include <string.h>
char*
strncat(char *s1, const char *s2, size_t n)
{
char *os1;
long nn;
os1 = s1;
nn = n;
while(*s1++)
;
s1--;
while(*s1++ = *s2++)
if(--nn < 0) {
s1[-1] = 0;
break;
}
return os1;
}