[PATCH] libstdc++: Use specific feature test macro for #if in

[Jonathan Wakely]

libstdc++-v3/ChangeLog:

        * include/bits/basic_string.h: Check __glibcxx_to_string instead
        of __cplusplus.
---

Tested x86_64-linux.

 libstdc++-v3/include/bits/basic_string.h | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/libstdc++-v3/include/bits/basic_string.h 
b/libstdc++-v3/include/bits/basic_string.h
index 9bbe16507d00..202a911f9ef3 100644
--- a/libstdc++-v3/include/bits/basic_string.h
+++ b/libstdc++-v3/include/bits/basic_string.h
@@ -56,11 +56,10 @@
 # include <bits/ranges_util.h>          // ranges::subrange
 #endif
 
-#if __cplusplus > 202302L
+#if __glibcxx_to_string >= 202306L // C++ >= 26
 # include <charconv>
 #endif
 
-
 #if ! _GLIBCXX_USE_CXX11_ABI
 # include "cow_string.h"
 #else
-- 
2.53.0