ref: fd8a2d81c3ddf6584d2b47f1b8efe30b66beb7b5 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; }