lfs/
Per-architecture copies of the hosted starforth binary. The hosted
Makefile copies the freshly built binary here as its last build step
(cp $(BINARY) lfs/$(ARCH_DIR)/starforth), separate from
build/<arch>/<profile>/, which is the working build-output tree.
amd64/starforth,arm64/starforth,riscv64/starforth— one binary per architecture, rebuilt whenever that architecture's hosted build runs.