[FrogAi]

The Makefile has five "cereal/*.capnp.go" rules that are the same rule with a different file name. This replaces them with one "%.capnp.go: %.capnp" pattern rule. "capnp compile -ogo" writes the ".go" file next to the schema, so "$<" gives the same command each rule had. The "capnp" target still lists the five files, so a new schema only needs adding there.

Audit report

Testing

In "golang:1.26.2-bookworm" with Debian's "capnp":

• "make -n capnp" and "make -n build" print the same commands as main with every schema newer than its ".go" file, with none newer, and with only "log.capnp" newer.
• A real "make capnp" after touching "custom.capnp" regenerated only "custom.capnp.go", and it came out the same as the committed file.

Difference

If a schema is deleted but its ".capnp.go" is left behind, main stops with "No rule to make target", while the pattern rule says "Nothing to be done" and keeps the old file.