ref: c28f07b5840216c4e83e1d3b21d8a9ed7c41f8f9 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; }