Help build lib optimize

hello, how to optimize the library

in my main build I have:

const target = b.standardTargetOptions(.{});
const optimize = b.standardOptimizeOption(.{});

but not in my build lib

maybe this is implied???

I need an explanation please

I did a test and put this in the main build
Is this right

	/// build Pmaitre
	/// zig 0.12.0 dev

const std = @import("std");

pub fn build(b: *std.Build) void {
	// Standard release options allow the person running `zig build` to select
	// between Debug, ReleaseSafe, ReleaseFast, and ReleaseSmall.
	const target   = b.standardTargetOptions(.{});
	const optimize = b.standardOptimizeOption(.{});

	// library			libary motor
	// zig-src			source projet
	// src_c			source c/c++
	// zig-src/lib		source .h 

	// Building the executable
	const Prog = b.addExecutable(.{
	.name = "Pmaitre",
	.root_source_file = .{ .path = "./Pmaitre.zig" },
	.target = target,
	.optimize = optimize,

	// for match use regex 

	// Resolve the 'library' dependency.
	const library_dep = b.dependency("library", .{
		.target = target,
		.optimize = optimize,

	// Import the smaller 'cursed' and 'utils' modules exported by the library. etc...
	Prog.root_module.addImport("cursed", library_dep.module("cursed"));
	Prog.root_module.addImport("utils", library_dep.module("utils"));
	Prog.root_module.addImport("match", library_dep.module("match"));
	Prog.root_module.addImport("forms", library_dep.module("forms"));
	Prog.root_module.addImport("grid",  library_dep.module("grid"));
	Prog.root_module.addImport("menu", library_dep.module("menu"));
	Prog.root_module.addImport("callpgm", library_dep.module("callpgm"));
	Prog.root_module.addImport("crypto", library_dep.module("crypto"));

	Prog.root_module.addImport("zmmap", library_dep.module("zmmap"));

	Prog.root_module.addImport("decimal", library_dep.module("decimal"));



The addModule options documentation says:

Unspecified options here will be inherited from parent Module when inserted into an import table.