[gcc r16-7457] libstdc++: Add missing exports for std::call_once on Windows [PR123908]

[Jonathan Wakely]

https://gcc.gnu.org/g:be6dad0edf123fc5cf953c248ca02cfcd7592094

commit r16-7457-gbe6dad0edf123fc5cf953c248ca02cfcd7592094
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Wed Feb 11 13:05:18 2026 +0000

    libstdc++: Add missing exports for std::call_once on Windows [PR123908]
    
    libstdc++-v3/ChangeLog:
    
            PR libstdc++/123908
            * config/abi/pre/gnu.ver (GLIBCXX_3.4.35): Add exports for
            std::__get_once_callable and std::__get_once_call.

Diff:
---
 libstdc++-v3/config/abi/pre/gnu.ver | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/libstdc++-v3/config/abi/pre/gnu.ver b/libstdc++-v3/config/abi/pre/gnu.ver
index fb78782eaf6d..fb968e122d8a 100644
--- a/libstdc++-v3/config/abi/pre/gnu.ver
+++ b/libstdc++-v3/config/abi/pre/gnu.ver
@@ -2586,6 +2586,12 @@ GLIBCXX_3.4.35 {
     _ZNSt12__cow_stringaSERKS_;
     _ZNSt12__cow_stringaSEOS_;
     _ZNKSt12__cow_string5c_strEv;
+
+#if defined (_WIN32) && !defined (__CYGWIN__)
+    _ZSt19__get_once_callablev;
+    _ZSt15__get_once_callv;
+#endif
+
 } GLIBCXX_3.4.34;
 
 # Symbols in the support library (libsupc++) have their own tag.