ref: a05f1d6ea1a7f7c26f9e17ba41274081f2b9b7b3 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; }