diff --git a/extra-builtins.cc b/extra-builtins.cc
index b9e0206..8bb0f75 100644
--- a/extra-builtins.cc
+++ b/extra-builtins.cc
@@ -72,9 +72,9 @@ static void cflags(EvalState & state, const PosIdx _pos,
     Value ** _args, Value & v)
 {
     auto attrs = state.buildBindings(3);
-    attrs.alloc("NIX_INCLUDE_DIRS").mkString(NIX_INCLUDE_DIRS);
-    attrs.alloc("NIX_CFLAGS_OTHER").mkString(NIX_CFLAGS_OTHER);
-    attrs.alloc("BOOST_INCLUDE_DIR").mkString(BOOST_INCLUDE_DIR);
+    attrs.alloc("NIX_INCLUDE_DIRS").mkString(NIX_INCLUDE_DIRS, state.mem);
+    attrs.alloc("NIX_CFLAGS_OTHER").mkString(NIX_CFLAGS_OTHER, state.mem);
+    attrs.alloc("BOOST_INCLUDE_DIR").mkString(BOOST_INCLUDE_DIR, state.mem);
     v.mkAttrs(attrs);
 }