patch 8.2.3406: on some systems tests fail without _REENTRANT

Problem:    On some systems tests fail without _REENTRANT. (Elimar
            Riesebieter)
Solution:   Add -D_REENTRANT in configure. (closes #7402)
diff --git a/src/version.c b/src/version.c
index 742f899..d56e443 100644
--- a/src/version.c
+++ b/src/version.c
@@ -756,6 +756,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    3406,
+/**/
     3405,
 /**/
     3404,