diff --git a/modules/apps.nix b/modules/apps.nix
index c49073d..1171dcf 100644
--- a/modules/apps.nix
+++ b/modules/apps.nix
@@ -3,12 +3,16 @@ let
   inherit (lib)
     mkOption
     types
-    getExe
     ;
   inherit (flake-parts-lib)
     mkTransposedPerSystemModule
     ;
 
+  getExe = lib.getExe or (
+    x:
+    "${lib.getBin x}/bin/${x.meta.mainProgram or (throw ''Package ${x.name or ""} does not have meta.mainProgram set, so I don't know how to find the main executable. You can set meta.mainProgram, or pass the full path to executable, e.g. program = "''${pkg}/bin/foo"'')}"
+  );
+
   programType = lib.types.coercedTo derivationType getExe lib.types.str;
 
   derivationType = lib.types.package // {