fix(build): nixos cross-building

Cargo.toml

@@ -31,6 +31,3 @@ gtk = ["dep:gtk4"]
 libnotify = ["dep:libnotify", "dep:gdk-pixbuf"]
 notify-rust = ["dep:notify-rust"]
 winapi = ["dep:winapi", "dep:winresource"]
-
-[workspace.metadata.cross.target.x86_64-pc-windows-gnu]
-image = "mglolenstine/gtk4-cross:rust-gtk-4.12"

Cross.toml

@@ -0,0 +1,2 @@
+[target.x86_64-pc-windows-gnu]
+image = "mglolenstine/gtk4-cross:rust-gtk-4.12"

docs/compiling.md

@@ -63,3 +63,23 @@ You'll get a desktop file contents, just edit paths here and write it to a new f
 All of these, with adding icons and other, makes this command: `make install` (using `gnumake` package) \
 But make sure, that you have `.local/bin` in the `PATH` variable, otherwise it won't work. \
 Now, if you'll run with the desktop file, GNotifications will work perfectly.
+
+# Cross-compiling
+
+## From Linux to Windows
+
+```bash
+./misc/build.sh
+```
+
+## From NixOS to Windows
+
+```bash
+nix-shell -p rustup gcc cargo-cross
+rustup toolchain install stable
+./misc/build.sh
+```
+
+## From Windows to Linux
+
+That's your problem