Port upstream commit 337455eb3a66176cc3f66d2c663a72cc7b4178bd to 2.4.59.

With 2.4.x, gentoo-infra saw crashes in nsscache during exit.
This patch was later reverted upstream because it was not portable to AIX And
was fixed in a different way in 2.5 & 2.6 releases.

original https://github.com/openldap/openldap/commit/337455eb3a66176cc3f66d2c663a72cc7b4178bd
revert: https://github.com/openldap/openldap/commit/5e13ef87a94491f9339dbca709db29e76741f1a9
AIX discussion: https://bugs.openldap.org/show_bug.cgi?id=10176
diff '--color=auto' -NuarwbB --exclude '*.rej' --exclude '*.orig' openldap-2.4.59.orig/libraries/libldap/init.c openldap-2.4.59/libraries/libldap/init.c
--- openldap-2.4.59.orig/libraries/libldap/init.c	2021-06-03 11:40:31.000000000 -0700
+++ openldap-2.4.59/libraries/libldap/init.c	2024-08-24 11:15:06.727326650 -0700
@@ -508,9 +508,6 @@
 		gopts->ldo_def_sasl_authcid = NULL;
 	}
 #endif
-#ifdef HAVE_TLS
-	ldap_int_tls_destroy( gopts );
-#endif
 }

 /*
diff '--color=auto' -NuarwbB --exclude '*.rej' --exclude '*.orig' openldap-2.4.59.orig/libraries/libldap/tls2.c openldap-2.4.59/libraries/libldap/tls2.c
--- openldap-2.4.59.orig/libraries/libldap/tls2.c	2024-08-24 11:14:46.910678897 -0700
+++ openldap-2.4.59/libraries/libldap/tls2.c	2024-08-24 11:15:38.103963402 -0700
@@ -155,6 +155,14 @@
 	tls_imp->ti_tls_destroy();
 }

+static void
+ldap_exit_tls_destroy( void )
+{
+	struct ldapoptions *lo = LDAP_INT_GLOBAL_OPT();
+
+	ldap_int_tls_destroy( lo );
+}
+
 /*
  * Initialize a particular TLS implementation.
  * Called once per implementation.
@@ -163,6 +171,7 @@
 tls_init(tls_impl *impl )
 {
 	static int tls_initialized = 0;
+	int rc;

 	if ( !tls_initialized++ ) {
 #ifdef LDAP_R_COMPILE
@@ -175,7 +184,10 @@
 #ifdef LDAP_R_COMPILE
 	impl->ti_thr_init();
 #endif
-	return impl->ti_tls_init();
+	rc = impl->ti_tls_init();
+
+	atexit( ldap_exit_tls_destroy );
+	return rc;
 }

 /*