The unpac monorepo manager self-hosting as a monorepo using unpac

Make fork_action.h a public_header

+1
+1
lib_eio/unix/dune
··· 1 1 (library 2 2 (name eio_unix) 3 3 (public_name eio.unix) 4 + (public_headers include/fork_action.h) 4 5 (foreign_stubs 5 6 (language c) 6 7 (include_dirs include)