[openssl/openssl] 2a6a04: tags: fix `make tags` target for out of tree builds

[Pauli]

  Branch: refs/heads/master
  Home:   https://github.com/openssl/openssl
  Commit: 2a6a04406b2f4e81bf8fd67c3fa19e8b18912710
      https://github.com/openssl/openssl/commit/2a6a04406b2f4e81bf8fd67c3fa19e8b18912710
  Author: Pauli <pauli at openssl.org>
  Date:   2023-06-01 (Thu, 01 Jun 2023)

  Changed paths:
    M Configurations/unix-Makefile.tmpl

  Log Message:
  -----------
  tags: fix `make tags` target for out of tree builds

Reviewed-by: Tomas Mraz <tomas at openssl.org>
Reviewed-by: Dmitry Belyavskiy <beldmit at gmail.com>
Reviewed-by: Todd Short <todd.short at me.com>
(Merged from https://github.com/openssl/openssl/pull/21079)