diff --git a/pkgs/applications/networking/instant-messengers/toxic/default.nix b/pkgs/applications/networking/instant-messengers/toxic/default.nix
index 6b33c712c61..b8f6fa1bfee 100644
--- a/pkgs/applications/networking/instant-messengers/toxic/default.nix
+++ b/pkgs/applications/networking/instant-messengers/toxic/default.nix
@@ -11,7 +11,7 @@ in stdenv.mkDerivation rec {
     sha256 = "01k32431zay1mdqvrw5qk0pjxb7gkcxr78w1a06g23b7ymjwfawv";
   };
 
-  makeFlags = [ "-Cbuild" "VERSION=${version}" ];
+  makeFlags = [ "-Cbuild" "VERSION=${version}" "PREFIX=$(out)" ];
   installFlags = [ "PREFIX=$(out)" ];
 
   buildInputs = [