add mainprogram wrapper

nix/srcds/default.nix

@@ -57,6 +57,11 @@
       patches = (prev.patches or []) ++ [./curl-symbol-downgrade.patch];
     }
   );
+
+  mainProgram =
+    if system == "x86_64-linux"
+    then "srcds_run_64"
+    else "srcds_run";
 in
   stdenvNoCC.mkDerivation {
     pname = "srcds-tf2";
@@ -82,10 +87,17 @@ in
 
       echo 440 > $out/steam_appid.txt
 
+      mkdir -p $out/bin
+
+      echo "#! /bin/sh" > $out/bin/${mainProgram}
+      echo "exec $out/${mainProgram} "'$@' >> $out/bin/${mainProgram}
+      chmod +x $out/bin/${mainProgram}
+
       runHook postInstall
     '';
 
     meta = with lib; {
+      inherit mainProgram;
       description = "TF2 dedicated server";
       homepage = "https://steamdb.info/app/440/";
       changelog = "https://store.steampowered.com/news/app/440?updates=true";