[gcc r13-10153] libstdc++: Fix preprocessor condition for AIX

[Jonathan Wakely]

https://gcc.gnu.org/g:a20dd9863fec80ff24399acf3e9568cc98a1f4a5

commit r13-10153-ga20dd9863fec80ff24399acf3e9568cc98a1f4a5
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Fri Mar 20 00:01:12 2026 +0000

    libstdc++: Fix preprocessor condition for AIX
    
    Only AIX uses getenv, so including <cstdlib> should be done when _AIX is
    defined, not when it's undefined.
    
    libstdc++-v3/ChangeLog:
    
            * src/c++20/tzdb.cc [_AIX]: Change #ifndef to #ifdef.
    
    (cherry picked from commit d2a883a0aee280a6f835eef7a1eda11a6798cc60)

Diff:
---
 libstdc++-v3/src/c++20/tzdb.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libstdc++-v3/src/c++20/tzdb.cc b/libstdc++-v3/src/c++20/tzdb.cc
index f9d2345cc922..83848cf67020 100644
--- a/libstdc++-v3/src/c++20/tzdb.cc
+++ b/libstdc++-v3/src/c++20/tzdb.cc
@@ -37,7 +37,7 @@
 #include <mutex>      // mutex
 #include <filesystem> // filesystem::read_symlink
 
-#ifndef _AIX
+#ifdef _AIX
 # include <cstdlib>   // getenv
 #endif