Package for Nix

Signed-off-by: Slendi <slendi@socopon.com>

.gitignore

@@ -1,2 +1,3 @@
 [Bb]uild*
 .cache
+result

flake.nix

@@ -1,4 +1,9 @@
+let
+  desc = "Single-file linear algebra math library for C++23.";
+in
 {
+  description = desc;
+
   inputs = {
     nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
     flake-utils.url = "github:numtide/flake-utils";
@@ -27,6 +32,52 @@
             pkg-config
           ];
         };
+
+        packages.default = pkgs.stdenv.mkDerivation {
+          pname = "smath";
+          version = "master";
+
+          src = ./.;
+
+          nativeBuildInputs = [ pkgs.copyPkgconfigItems ];
+
+          pkgconfigItems = [
+            (pkgs.makePkgconfigItem rec {
+              name = "smath";
+              version = "1";
+              cflags = [ "-I${variables.includedir}" ];
+              variables = rec {
+                prefix = "${placeholder "out"}";
+                includedir = "${prefix}/include";
+              };
+              description = desc;
+            })
+          ];
+
+          dontBuild = true;
+
+          installPhase = ''
+            						runHook preInstall
+                        mkdir -p $out/include
+                        cp include/*.hpp $out/include/
+            						runHook postInstall
+          '';
+
+          meta = with pkgs.lib; {
+            description = desc;
+            homepage = "https://github.com/slendidev/smath";
+            license = licenses.asl20;
+            platforms = platforms.all;
+            maintainers = [
+              {
+                name = "Slendi";
+                email = "slendi@socopon.com";
+                github = "slendidev";
+                githubId = 32436619;
+              }
+            ];
+          };
+        };
       }
     );
 }