Historical/candidate build record for compare.c. This file contains a function without main.

Historical QA, 2026-10-12: gcc13.3.0 with gcc -Wall -Wextra -o prog compare.c failed to link because main was undefined. No executable, object file or assembly listing was retained.

Unrun historical candidate, not a working standalone build recipe:
gcc -O0 -g -o mark compare.c

-O0 disables most optimization passes; it does not guarantee one instruction listing.
-g requests debugger information; -o mark names the output.
These options do not supply main. Do not run this command for the lesson.
A later component build or harness would need its own explicit design and evidence record.