diff --git a/pkgs/development/libraries/boost/generic.nix b/pkgs/development/libraries/boost/generic.nix
index 2d0a5a63d6f..82bcd49592d 100644
--- a/pkgs/development/libraries/boost/generic.nix
+++ b/pkgs/development/libraries/boost/generic.nix
@@ -103,7 +103,7 @@ stdenv.mkDerivation {
 
   inherit src version;
 
-  patchFlags = "";
+  patchFlags = [];
 
   patches = patches
   ++ optional stdenv.isDarwin (