diff --git a/pkgs/build-support/setup-hooks/wrap-gapps-hook/wrap-gapps-hook.sh b/pkgs/build-support/setup-hooks/wrap-gapps-hook/wrap-gapps-hook.sh
index 0acf4a8e6f8d..b2e52f574a52 100644
--- a/pkgs/build-support/setup-hooks/wrap-gapps-hook/wrap-gapps-hook.sh
+++ b/pkgs/build-support/setup-hooks/wrap-gapps-hook/wrap-gapps-hook.sh
@@ -34,7 +34,7 @@ gappsWrapperArgsHook() {
     done
 }
 
-preFixupPhases+=" gappsWrapperArgsHook"
+appendToVar preFixupPhases gappsWrapperArgsHook
 
 wrapGApp() {
     local program="$1"