24T2 Q8 — Append two lists

stdin: two lines, each a list of ints separated by spaces (a line may be empty). Append the second list to the end of the first and print the result on one line, space-separated (empty line if both are empty).

Single-file C (gcc -O0 -Wall). Self-contained reframing of the exam's ADT-completion question. From COMP2521 24T2 Sample.