build: add statically linked output

if only something like this was possible with wayland and others...

Cargo.toml

@@ -10,6 +10,9 @@ thiserror = "2.0.18"
 version = "1.30"
 default-features = false
 features = ["std", "float"]
+[dependencies.gmp-mpfr-sys]
+version = "*"
+features = ["force-cross"]
 
 [profile.release]
 lto = true

flake.nix

@@ -10,31 +10,43 @@
     inputs.flake-utils.lib.eachDefaultSystem (
       system:
       let
-        pkgs = import inputs.nixpkgs { inherit system; };
+        pkgs = inputs.nixpkgs.legacyPackages.${system};
+        lib = inputs.nixpkgs.lib;
+
+        src = lib.sourceFilesBySuffices ./. [
+          "Cargo.toml"
+          "Cargo.lock"
+          ".rs"
+        ];
 
-        src = ./.;
         cargoToml = fromTOML (builtins.readFile "${src}/Cargo.toml");
         name = cargoToml.package.name;
 
-        crate = pkgs.rustPlatform.buildRustPackage {
-          inherit name src;
+        bin =
+          {
+            rustPlatform,
+            m4,
+          }:
+          rustPlatform.buildRustPackage {
+            inherit name src;
 
-          cargoLock.lockFile = "${src}/Cargo.lock";
+            cargoLock.lockFile = "${src}/Cargo.lock";
 
-          nativeBuildInputs = with pkgs; [
-            m4
-          ];
-        };
+            nativeBuildInputs = [
+              m4
+            ];
+          };
+
+        default = pkgs.callPackage bin { };
       in
       {
-        packages.default = crate;
+        packages.default = default;
+        packages.static = pkgs.pkgsStatic.callPackage bin { };
 
         devShells.default = pkgs.mkShell {
-          inputsFrom = [ crate ];
+          inputsFrom = [ default ];
 
           packages = with pkgs; [
-            rustc
-            cargo
             clippy
             rustfmt
             rust-analyzer