fix(stdexec): added adaption to ensure successful build with stdexec

Signed-off-by: David Hua <tkrd1205@gmail.com>

Author: sususu5

libs/core/execution_base/include/hpx/execution_base/stdexec_forward.hpp

@@ -162,7 +162,6 @@ namespace hpx::execution::experimental {
 
     // Domain
     HPX_CXX_EXPORT using stdexec::default_domain;
-    HPX_CXX_EXPORT using stdexec::dependent_domain;
 
     // Execute
     HPX_CXX_EXPORT using stdexec::execute;
@@ -237,12 +236,10 @@ namespace hpx::execution::experimental {
     HPX_CXX_EXPORT using stdexec::sends_stopped;
     HPX_CXX_EXPORT using stdexec::value_types_of_t;
 
-    HPX_CXX_EXPORT using stdexec::make_completion_signatures;
     HPX_CXX_EXPORT using stdexec::transform_completion_signatures;
     HPX_CXX_EXPORT using stdexec::transform_completion_signatures_of;
 
     // Transform sender
-    HPX_CXX_EXPORT using stdexec::transform_env;
     HPX_CXX_EXPORT using stdexec::transform_sender;
     HPX_CXX_EXPORT using stdexec::transform_sender_result_t;
     HPX_CXX_EXPORT using stdexec::transform_sender_t;

libs/core/executors/include/hpx/executors/thread_pool_scheduler.hpp

@@ -298,6 +298,20 @@ namespace hpx::execution::experimental {
                 {
                     return e.sched;
                 }
+
+                // clang-format off
+                template <typename CPO,
+                    HPX_CONCEPT_REQUIRES_(
+                        meta::value<meta::one_of<
+                            CPO, set_value_t, set_stopped_t>>
+                    )>
+                // clang-format on
+                constexpr auto query(
+                    hpx::execution::experimental::get_completion_scheduler_t<
+                        CPO>) const noexcept
+                {
+                    return sched;
+                }
             };
 
             friend constexpr env tag_invoke(
@@ -355,6 +369,11 @@ namespace hpx::execution::experimental {
             return {sched};
         }
 
+        constexpr sender<thread_pool_policy_scheduler> schedule() const
+        {
+            return {*this};
+        }
+
         void policy(Policy policy) noexcept
         {
             policy_ = HPX_MOVE(policy);