[Bug bootstrap/83102] go bootstrap error in ast-dump.cc due to __is_invocable failure

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83102

--- Comment #4 from Jonathan Wakely <redi at gcc dot gnu.org> ---
If we want to relax the check this should work:

--- a/libstdc++-v3/include/bits/stl_tree.h
+++ b/libstdc++-v3/include/bits/stl_tree.h
@@ -448,8 +448,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION

       typedef __gnu_cxx::__alloc_traits<_Node_allocator> _Alloc_traits;

-#if __cplusplus >= 201103L
-      static_assert(__is_invocable<const _Compare&, const _Key&, const
_Key&>{},
+#if __cplusplus >= 201703L
+      // LWG DR 2542: Missing const requirements for associative containers
+      static_assert(is_invocable_v<const _Compare&, const _Key&, const _Key&>,
+         "comparison object must be invocable with two arguments of key
type");
+#elif __cplusplus >= 201103L
+      static_assert(__is_invocable<_Compare&, const _Key&, const _Key&>{},
          "comparison object must be invocable with two arguments of key
type");
 #endif