diff --git a/pkgs/development/libraries/waylandpp/default.nix b/pkgs/development/libraries/waylandpp/default.nix
index 61ac0a51cfdc..d1ddfa6cbc07 100644
--- a/pkgs/development/libraries/waylandpp/default.nix
+++ b/pkgs/development/libraries/waylandpp/default.nix
@@ -34,9 +34,11 @@ stdenv.mkDerivation (finalAttrs: {
   ];
 
   # Complains about not being able to find the fontconfig config file otherwise
-  env.FONTCONFIG_FILE = lib.optional docSupport (makeFontsConf {
-    fontDirectories = [ ];
-  });
+  env = lib.optionalAttrs docSupport {
+    FONTCONFIG_FILE = makeFontsConf {
+      fontDirectories = [ ];
+    };
+  };
 
   nativeBuildInputs = [
     cmake