diff --git a/pkgs/development/compilers/opensmalltalk-vm/default.nix b/pkgs/development/compilers/opensmalltalk-vm/default.nix
index 3ee6953ba4de..a049e3e8abec 100644
--- a/pkgs/development/compilers/opensmalltalk-vm/default.nix
+++ b/pkgs/development/compilers/opensmalltalk-vm/default.nix
@@ -71,7 +71,7 @@ let
 
       configureFlags = [ "--with-scriptname=${scriptName}" ] ++ configureFlags;
 
-      buildFlags = "all";
+      buildFlags = [ "all" ];
 
       enableParallelBuilding = true;