--- libs/filesystem/src/operations.cpp.orig	2007-10-24 16:17:09.463582244 -0400
+++ libs/filesystem/src/operations.cpp	2007-10-24 16:21:07.178586365 -0400
@@ -1280,7 +1280,8 @@
           && defined(_POSIX_THREAD_SAFE_FUNCTIONS) \
           && defined(_SC_THREAD_SAFE_FUNCTIONS) \
           && (_POSIX_THREAD_SAFE_FUNCTIONS+0 >= 0) \
-          && (!defined(__hpux) || (defined(__hpux) && defined(_REENTRANT)))
+          && (!defined(__hpux) || (defined(__hpux) && defined(_REENTRANT))) \
+          && (defined(_AIX) && defined(__THREAD_SAFE))
           if ( ::sysconf( _SC_THREAD_SAFE_FUNCTIONS ) >= 0 )
             { return ::readdir_r( dirp, entry, result ); }
     #     endif