ref: 3e94fbcf9c6caa7cde6051bec82cae3b1c8d3e11 dir: /sys/src/ape/lib/ap/gen/strcat.c/
#include <string.h> char* strcat(char *s1, const char *s2) { strcpy(strchr(s1, 0), s2); return s1; }