Add support for rule hints

A rule hint is a target attribute, for example:

[rule_hint=cxx] exe{hello}: c{hello}

Rule hints can be used to resolve ambiguity when multiple rules match the same
target as well as to override an unambiguous match.

1 files changed, 1 insertions, 1 deletions

diff --git a/libbuild2/in/target.cxx b/libbuild2/in/target.cxx
index d9bc8a7..d548453 100644
--- a/libbuild2/in/target.cxx
+++ b/libbuild2/in/target.cxx
@@ -53,7 +53,7 @@ namespace build2
       &in_pattern,
       &target_print_1_ext_verb,          // Same as file.
       &in_search,
-      false
+      target_type::flag::none
     };
   }
 }