diff --git a/pkgs/applications/window-managers/spectrwm/default.nix b/pkgs/applications/window-managers/spectrwm/default.nix
index ba43403d9bbb..1eb19e2de6f9 100644
--- a/pkgs/applications/window-managers/spectrwm/default.nix
+++ b/pkgs/applications/window-managers/spectrwm/default.nix
@@ -39,7 +39,7 @@ stdenv.mkDerivation {
     subdir = if stdenv.isDarwin then "osx" else "linux";
   in "spectrwm-SPECTRWM_2_7_2/${subdir}";
 
-  makeFlags="PREFIX=$(out)";
+  makeFlags = [ "PREFIX=$(out)" ];
   installPhase = "PREFIX=$out make install";
 
   meta = with stdenv.lib; {