Add icon and build script

Cargo.toml

@@ -6,4 +6,7 @@ edition = "2021"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-winapi = { version = "0.3", features = ["winuser"] }
+winapi = { version = "0.3", features = ["winuser"] }
+
+[target.'cfg(windows)'.build-dependencies]
+winres = "0.1"

build.rs

@@ -0,0 +1,12 @@
+use std::io;
+#[cfg(windows)] use winres::WindowsResource;
+
+fn main() -> io::Result<()> {
+    #[cfg(windows)] {
+        WindowsResource::new()
+            // This path can be absolute, or relative to your crate root.
+            .set_icon("assets/icon.ico")
+            .compile()?;
+    }
+    Ok(())
+}