force recent AIX versions to check for strerror_r

configure.ac

@@ -915,6 +915,7 @@ printf("just fine");
 #endif
 ],
  [ AC_MSG_RESULT([yes])
+   RECENTAIX=yes
    OPT_THREAD=off ],
  [ AC_MSG_RESULT([no]) ]
 )
@@ -959,6 +960,16 @@ else
 
 fi
 
+dnl for recent AIX versions, we skip all the thread-safe checks above since
+dnl they claim a thread-safe libc using the standard API. But the man page
+dnl says strerror() is not thread-safe, so we check for this only!
+
+if test "x$RECENTAIX" = "xyes"; then
+  dnl is there a strerror_r()
+  CURL_CHECK_STRERROR_R()
+fi
+
+
 dnl **********************************************************************
 dnl Back to "normal" configuring
 dnl **********************************************************************