[gcc r13-453] libstdc++: Make std::thread::_State private

[gcc r13-453] libstdc++: Make std::thread::_State private

[Jonathan Wakely]

https://gcc.gnu.org/g:7f40ac326a1f347a826636bc392a4db185b78b95

commit r13-453-g7f40ac326a1f347a826636bc392a4db185b78b95
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Thu May 12 20:46:55 2022 +0100

    libstdc++: Make std::thread::_State private
    
            * include/bits/std_thread.h (thread::_State, thread::_State_ptr):
            Declare as private unless _GLIBCXX_THREAD_IMPL is defined.
            * src/c++11/thread.cc (_GLIBCXX_THREAD_IMPL): Define.

Diff:
---
 libstdc++-v3/include/bits/std_thread.h | 21 ++++++++++++---------
 libstdc++-v3/src/c++11/thread.cc       |  1 +
 2 files changed, 13 insertions(+), 9 deletions(-)

diff --git a/libstdc++-v3/include/bits/std_thread.h b/libstdc++-v3/include/bits/std_thread.h
index f67bc114591..d7fc0123564 100644
--- a/libstdc++-v3/include/bits/std_thread.h
+++ b/libstdc++-v3/include/bits/std_thread.h
@@ -79,15 +79,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
   {
   public:
 #ifdef _GLIBCXX_HAS_GTHREADS
-    // Abstract base class for types that wrap arbitrary functors to be
-    // invoked in the new thread of execution.
-    struct _State
-    {
-      virtual ~_State();
-      virtual void _M_run() = 0;
-    };
-    using _State_ptr = unique_ptr<_State>;
-
     using native_handle_type = __gthread_t;
 #else
     using native_handle_type = int;
@@ -216,6 +207,18 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     hardware_concurrency() noexcept;
 
 #ifdef _GLIBCXX_HAS_GTHREADS
+#ifndef _GLIBCXX_THREAD_IMPL
+  private:
+#endif
+    // Abstract base class for types that wrap arbitrary functors to be
+    // invoked in the new thread of execution.
+    struct _State
+    {
+      virtual ~_State();
+      virtual void _M_run() = 0;
+    };
+    using _State_ptr = unique_ptr<_State>;
+
   private:
     template<typename _Callable>
       struct _State_impl : public _State
diff --git a/libstdc++-v3/src/c++11/thread.cc b/libstdc++-v3/src/c++11/thread.cc
index 669fbb045e2..707a4ad415b 100644
--- a/libstdc++-v3/src/c++11/thread.cc
+++ b/libstdc++-v3/src/c++11/thread.cc
@@ -24,6 +24,7 @@
 
 
 #define _GLIBCXX_THREAD_ABI_COMPAT 1
+#define _GLIBCXX_THREAD_IMPL 1
 #include <memory> // include this first so <thread> can use shared_ptr
 #include <thread>
 #include <system_error>