[gcc r16-8608] libstdc++: Define __cpp_lib_stdbit_h and __cpp_lib_stdckdint_h feature test macros.

[Tomasz Kaminski]

https://gcc.gnu.org/g:62d243c91c05b13490aac10b4faad81e86ea6bbf

commit r16-8608-g62d243c91c05b13490aac10b4faad81e86ea6bbf
Author: Tomasz Kamiński <tkaminsk@redhat.com>
Date:   Tue Apr 14 16:30:36 2026 +0200

    libstdc++: Define __cpp_lib_stdbit_h and __cpp_lib_stdckdint_h feature test macros.
    
    This implements LWG4550: Need new feature test macros for <stdckdint.h>
    and <stdbit.h>.
    
    libstdc++-v3/ChangeLog:
    
            * include/bits/version.def (stdbit_h, stdckdint_h): Define.
            * include/bits/version.h: Regenerate.
            * include/c_compatibility/stdbit.h (__cpp_lib_stdbit_h): Define
            and use it in guards.
            * include/c_compatibility/stdckdint.h (__cpp_lib_stdckdint_h):
            Define and use it in guards.
    
    Reviewed-by: Jonathan Wakely <jwakely@redhat.com>
    Signed-off-by: Tomasz Kamiński <tkaminsk@redhat.com>

Diff:
---
 libstdc++-v3/include/bits/version.def            | 16 ++++++++++++++++
 libstdc++-v3/include/bits/version.h              | 20 ++++++++++++++++++++
 libstdc++-v3/include/c_compatibility/stdbit.h    |  8 ++++++--
 libstdc++-v3/include/c_compatibility/stdckdint.h |  8 ++++++--
 4 files changed, 48 insertions(+), 4 deletions(-)

diff --git a/libstdc++-v3/include/bits/version.def b/libstdc++-v3/include/bits/version.def
index 94fc1f859932..13dba4d63789 100644
--- a/libstdc++-v3/include/bits/version.def
+++ b/libstdc++-v3/include/bits/version.def
@@ -1871,6 +1871,22 @@ ftms = {
   };
 };
 
+ftms = {
+  name = stdbit_h;
+  values = {
+    v = 202603;
+    cxxmin = 26;
+  };
+};
+
+ftms = {
+  name = stdckdint_h;
+  values = {
+    v = 202603;
+    cxxmin = 26;
+  };
+};
+
 ftms = {
   name = adaptor_iterator_pair_constructor;
   values = {
diff --git a/libstdc++-v3/include/bits/version.h b/libstdc++-v3/include/bits/version.h
index 402e67580eb3..743f7e29fe29 100644
--- a/libstdc++-v3/include/bits/version.h
+++ b/libstdc++-v3/include/bits/version.h
@@ -2076,6 +2076,26 @@
 #endif /* !defined(__cpp_lib_stdatomic_h) */
 #undef __glibcxx_want_stdatomic_h
 
+#if !defined(__cpp_lib_stdbit_h)
+# if (__cplusplus >  202302L)
+#  define __glibcxx_stdbit_h 202603L
+#  if defined(__glibcxx_want_all) || defined(__glibcxx_want_stdbit_h)
+#   define __cpp_lib_stdbit_h 202603L
+#  endif
+# endif
+#endif /* !defined(__cpp_lib_stdbit_h) */
+#undef __glibcxx_want_stdbit_h
+
+#if !defined(__cpp_lib_stdckdint_h)
+# if (__cplusplus >  202302L)
+#  define __glibcxx_stdckdint_h 202603L
+#  if defined(__glibcxx_want_all) || defined(__glibcxx_want_stdckdint_h)
+#   define __cpp_lib_stdckdint_h 202603L
+#  endif
+# endif
+#endif /* !defined(__cpp_lib_stdckdint_h) */
+#undef __glibcxx_want_stdckdint_h
+
 #if !defined(__cpp_lib_adaptor_iterator_pair_constructor)
 # if (__cplusplus >= 202100L) && _GLIBCXX_HOSTED
 #  define __glibcxx_adaptor_iterator_pair_constructor 202106L
diff --git a/libstdc++-v3/include/c_compatibility/stdbit.h b/libstdc++-v3/include/c_compatibility/stdbit.h
index 1fb691e36c18..fa4ec0414c6e 100644
--- a/libstdc++-v3/include/c_compatibility/stdbit.h
+++ b/libstdc++-v3/include/c_compatibility/stdbit.h
@@ -29,7 +29,11 @@
 #ifndef _GLIBCXX_STDBIT_H
 #define _GLIBCXX_STDBIT_H
 
-#if __cplusplus > 202302L
+#define __glibcxx_want_stdbit_h
+#include <bits/version.h>
+
+#ifdef __cpp_lib_stdbit_h // C++ >= 26
+
 #include <bit>
 
 #define __STDC_VERSION_STDBIT_H__ 202311L
@@ -577,6 +581,6 @@ _GLIBCXX_STDBIT_FUNC(stdc_bit_floor);
 _GLIBCXX_STDBIT_FUNC(stdc_bit_ceil);
 #undef _GLIBCXX_STDBIT_FUNC
 #endif // !DOXYGEN
-#endif // C++26
+#endif // __cpp_lib_stdbit_h
 
 #endif // _GLIBCXX_STDBIT_H
diff --git a/libstdc++-v3/include/c_compatibility/stdckdint.h b/libstdc++-v3/include/c_compatibility/stdckdint.h
index 5bdf4dc7b24b..0f0b30cc8997 100644
--- a/libstdc++-v3/include/c_compatibility/stdckdint.h
+++ b/libstdc++-v3/include/c_compatibility/stdckdint.h
@@ -29,7 +29,11 @@
 #ifndef _GLIBCXX_STDCKDINT_H
 #define _GLIBCXX_STDCKDINT_H
 
-#if __cplusplus > 202302L
+#define __glibcxx_want_stdckdint_h
+#include <bits/version.h>
+
+#ifdef __cpp_lib_stdckdint_h // C++ >= 26
+
 #include <type_traits>
 #include <concepts>
 
@@ -96,6 +100,6 @@ using __gnu_cxx::ckd_sub;
 using __gnu_cxx::ckd_mul;
 #endif
 
-#endif // C++26
+#endif // __cpp_lib_stdckdint_h
 
 #endif // _GLIBCXX_STDCKDINT_H