There is an updated pull request by klarasm against master on the void-packages repository

https://github.com/klarasm/void-packages openldap-2.6
https://github.com/void-linux/void-packages/pull/41948

openldap: update to 2.6.4
The 2.4 branch is not maintained anymore and I don't know if there's much advantage to going to 2.5 instead of 2.6

Some shared libraries have changed name so this updates common/shlibs.

As this is a major update the ldap database should be backed up and recreated as per https://www.openldap.org/doc/admin26/maintenance.html

#### Testing the changes
- I tested the changes in this PR: **YES** (mainly openldap, mit-krb5 and cyrus-sasl)
- I haven't tested the revbumped packages that much, other than building with their test suite

I have upgraded my ldap setup to this version. It's not very complicated so may not be great for coverage.
Basically:
- two nodes, with normal syncrepl and gssapi/kerberos for authentication
- the ldap directory is used as database backend for my kerberos setup
- I have a few machines setup with kerberos for authentication and ldap as id provider (some with sssd and some with nslcd)

<!--
Packages that depend on libldap:
- [x] FreeRADIUS-3.0.26_1 (out of date, newest version is 3.2.1)
- [x] alpine-2.26_1
- [x] anjuta-3.34.0_4 (fix faulty detection of webkit2gtk)
- [x] apache-2.4.54_2 (out of date, newest version is 2.4.55)
- [x] apr-util-ldap-1.6.1_13 (update to 1.6.2)
- [x] audit-3.0.3_4 (out of date, newest version is 3.0.9)
- [x] autofs-5.1.8_2 (out of date, newest version is 5.1.9)
- [x] claws-mail-4.1.1_1
- [x] cyrus-sasl-2.1.27_9 (out of date, newest version is 2.1.28)
- [x] dovecot-plugin-ldap-2.3.20_1
- [x] dovecot-plugin-pigeonhole-ldap-0.5.20_1
- [x] evolution-3.46.2_1
- [x] evolution-data-server-3.46.2_1
- [x] gnupg-2.3.8_1
- [x] gnupg1-1.4.23_1
- [x] kldap-22.08.2_1
- [x] ldapvi-1.7_11
- [x] libnfsidmap-2.5.4_2
- [x] libreoffice-common-7.4.3.2_1
- [x] lighttpd-1.4.68_1
- [x] log4cxx-0.10.0_4 (update to 1.0.0)
- [x] lua54-lualdap-1.2.5_3 (out of date, newest version is 1.3.0)
- [x] mit-krb5-libs-1.18.3_2 (update to 1.20.1)
- [x] monitoring-plugins-2.3.2_1 (out of date, newest version is 2.3.3)
- [x] nss-pam-ldapd-0.9.12_1
- [x] php8.0-ldap-8.0.25_1 (out of date, newest version is 8.0.27)
- [x] php8.1-ldap-8.1.12_1 (out of date, newest version in branch is 8.1.14. 8.2.1 is also available)
- [x] postfix-3.7.3_1
- [x] python3-ldap-3.2.0_5 (update to 3.4.3)
- [x] quota-4.09_1
- [x] samba-4.14.12_2 (out of date, newest version is 4.17.5)
- [x] seahorse-43.0_1
- [x] squid-5.7_1
- [x] sssd-2.4.0_5 (out of date, latest version is 2.8.2)
- [x] sylpheed-3.7.0_8
- [x] virtuoso-base-7.2.5.1_3 (update to 7.2.8)
- [x] x2goclient-4.1.2.2_2
-->
This PR should not be merged before:
- [x] log4cxx-1.0.0 #42632
- [x] mit-krb5 1.20.1 #42633
- [x] python3-ldap-3.4.3 #42634
- [ ] apr-util-1.6.3 #42636
- [ ] virtuoso-7.2.9 #42666

[ci skip] again.

#### Local build testing
See latest comment.
<!--
- I built this PR locally for my native architecture, (x86_64-glibc)
- I built this PR locally for my native architecture, (x86_64-musl). Build issues:
  - audit-3.0.3_4 (out of date, newest version is 3.0.9) already failing on master branch
  - dovecot-plugin-ldap-2.3.20_1 already failing on master branch
  - dovecot-plugin-pigeonhole-ldap-0.5.20_1 test suite passes if dovecot is built without checks first
  - evolution-3.46.2_1 tests are not found on master branch and thus passes without running them
  - evolution-data-server-3.46.2_1 already failing on master branch

- I built this PR locally for these architectures (if supported. mark crossbuilds):
  - aarch64-musl (x2go-client, virtuoso, sssd, squid, libreoffice and FreeRADIUS fail due to cross-compilation, all other complete)
  - armv6l-musl (x2go-client, virtuoso, sssd, squid, libreoffice and FreeRADIUS fail due to cross-compilation, all other complete)
  - armv7l (x2go-client, virtuoso, sssd, squid, libreoffice and FreeRADIUS fail due to cross-compilation, all other complete)
  - i686 (apr-util seems to require x86_64 and complains that selected cpu does not support that. This makes other package that depend on apr-util fail as well: anjuta, apache, php, php8.0 and log4cxx. virtuoso, sssd, libreoffice, FreeRADIUS, squid and gnupg1 probably fails due to cross-compilation)
-->

A patch file from https://github.com/void-linux/void-packages/pull/41948.patch is attached