diff --git a/libbuild2-autoconf/libbuild2/autoconf/init.cxx b/libbuild2-autoconf/libbuild2/autoconf/init.cxx
index db41fd0..8c1017d 100644
--- a/libbuild2-autoconf/libbuild2/autoconf/init.cxx
+++ b/libbuild2-autoconf/libbuild2/autoconf/init.cxx
@@ -19,61 +19,64 @@ namespace build2
     init (scope& rs,
           scope& bs,
           const location& l,
-          bool,
+          bool first,
           bool,
           module_init_extra&)
     {
       tracer trace ("autoconf::init");
       l5 ([&]{trace << "for " << bs;});
 
-      // Load in.base (in.* variables, in{} target type).
-      //
-      load_module (rs, rs, "in.base", l);
-
-      // Enter variables.
-      //
+      if (first)
       {
-        // All the variables we enter are qualified so go straight for the
-        // public variable pool.
+        // Load in.base (in.* variables, in{} target type).
         //
-        auto& vp (rs.var_pool (true /* public */));
+        load_module (rs, rs, "in.base", l);
 
-        // Configuration file flavor. Valid values are `autoconf` (default),
-        // `cmake`, and `meson`.
+        // Enter variables.
         //
-        vp.insert<string> ("autoconf.flavor");
+        {
+          // All the variables we enter are qualified so go straight for the
+          // public variable pool.
+          //
+          auto& vp (rs.var_pool (true /* public */));
 
-        // Built-in checks prefix.
-        //
-        vp.insert<string> ("autoconf.prefix");
+          // Configuration file flavor. Valid values are `autoconf` (default),
+          // `cmake`, and `meson`.
+          //
+          vp.insert<string> ("autoconf.flavor");
 
-        // Substitution map (an alias for in.substitutions).
-        //
-        vp.insert_alias (*vp.find ("in.substitutions"),
-                         "autoconf.substitutions");
+          // Built-in checks prefix.
+          //
+          vp.insert<string> ("autoconf.prefix");
 
-        // Alias map. The key is the new name and the value is the aliased
-        // (old) name.
+          // Substitution map (an alias for in.substitutions).
+          //
+          vp.insert_alias (*vp.find ("in.substitutions"),
+                           "autoconf.substitutions");
+
+          // Alias map. The key is the new name and the value is the aliased
+          // (old) name.
+          //
+          // Note that this map is only consulted when resolving build-in
+          // checks and the names should include the prefix, if any.
+          //
+          vp.insert<map<string, string>> ("autoconf.aliases");
+        }
+
+        // Register the rule.
         //
-        // Note that this map is only consulted when resolving build-in checks
-        // and the names should include the prefix, if any.
+        // @@ TODO: this will be ambiguous, for example, version.in rule. Note
+        //    also that if we register it for cc{}, then it will always take
+        //    precedence over version.in, which is probably something we don't
+        //    want. In fact, we would have liked it to be of lower precedence
+        //    since version.in will only match if there is dependency on
+        //    manifest.
         //
-        vp.insert<map<string, string>> ("autoconf.aliases");
+        rs.insert_rule<file> (perform_update_id,   "autoconf.in", rule_);
+        rs.insert_rule<file> (perform_clean_id,    "autoconf.in", rule_);
+        rs.insert_rule<file> (configure_update_id, "autoconf.in", rule_);
       }
 
-      // Register the rule.
-      //
-      // @@ TODO: this will be ambiguous, for example, version.in rule. Note
-      //    also that if we register it for cc{}, then it will always take
-      //    precedence over version.in, which is probably something we don't
-      //    want. In fact, we would have liked it to be of lower precedence
-      //    since version.in will only match if there is dependency on
-      //    manifest.
-      //
-      rs.insert_rule<file> (perform_update_id,   "autoconf.in", rule_);
-      rs.insert_rule<file> (perform_clean_id,    "autoconf.in", rule_);
-      rs.insert_rule<file> (configure_update_id, "autoconf.in", rule_);
-
       return true;
     }