build: use binary mask for build status flags
build: use binary mask for build status flags

If multiple builds with fail with different errors it will be reflected
in the status code.

eg.

	103 => timeout + hash mismatch
	105 => timeout + check mismatch
	106 => hash mismatch + check mismatch
	107 => timeout + hash mismatch + check mismatch

ehmry/nix,rycee/nix,rycee/nix,dtzWill/nix,ehmry/nix,rycee/nix,dtzWill/nix,ehmry/nix,dtzWill/nix,dtzWill/nix,pikajude/nix,pikajude/nix,ehmry/nix,NixOS/nix,NixOS/nix,NixOS/nix,NixOS/nix,dtzWill/nix,NixOS/nix,rycee/nix,pikajude/nix,rycee/nix,ehmry/nix,ehmry/nix