Backport fix to also block SIGPIPE during the atfork() handler.

--- nss_ldap-253/ldap-nss.c	2008-05-28 17:11:19.000000000 -0400
+++ nss_ldap-253/ldap-nss.c	2008-05-28 17:15:10.000000000 -0400
@@ -517,7 +517,7 @@
 do_atfork_prepare (void)
 {
   debug ("==> do_atfork_prepare");
-  NSS_LDAP_LOCK (__lock);
+  _nss_ldap_enter ();
   debug ("<== do_atfork_prepare");
 }
 
@@ -525,7 +525,7 @@
 do_atfork_parent (void)
 {
   debug ("==> do_atfork_parent");
-  NSS_LDAP_UNLOCK (__lock);
+  _nss_ldap_leave ();
   debug ("<== do_atfork_parent");
 }
 
@@ -534,7 +534,7 @@
 {
   debug ("==> do_atfork_child");
   do_close_no_unbind ();
-  NSS_LDAP_UNLOCK (__lock);
+  _nss_ldap_leave ();
   debug ("<== do_atfork_child");
 }