Allow for target group members to remain unresolved

This, for example, can happen when we have a fallback rule for dist(update)
or configure(update).

1 files changed, 4 insertions, 2 deletions

diff --git a/build/algorithm b/build/algorithm
index 375cebb..d144d6c 100644
--- a/build/algorithm
+++ b/build/algorithm
@@ -121,8 +121,10 @@ namespace build
   void
   search_and_match_prerequisite_members (action, target&, const dir_path&);
 
-  // Unless already available, match, and, if necessary, execute
-  // the group in order to obtain its members list.
+  // Unless already available, match, and, if necessary, execute the group
+  // in order to obtain its members list. Note that even after that the
+  // member's list might still not be available (e.g., if some wildcard/
+  // fallback rule matched).
   //
   group_view
   resolve_group_members (action, target&);