databases/mysql84-server: fix build with clang and libc++ 19

As noted in the libc++ 19 release notes [1], std::char_traits<> is now
only provided for char, char8_t, char16_t, char32_t and wchar_t, and any
instantiation for other types will fail.

This causes databases/mysql84-server to fail to compile with clang 19
and libc++ 19, resulting in errors similar to:

    /usr/include/c++/v1/string:820:42: error: implicit instantiation of
undefined template 'std::char_traits<unsigned char>'
      820 |   static_assert(is_same<_CharT, typename
traits_type::char_type>::value,
          |                                          ^
    /wrkdirs/usr/ports/databases/mysql84-client/work/mysql-8.4.2/sql/rpl_log_encryption.h:821:14:
note: in instantiation of template class 'std::basic_string<unsigned
char>' requested here
      821 |   Key_string m_encrypted_password;
          |              ^
    /usr/include/c++/v1/__fwd/string.h:23:29: note: template is declared
here
       23 | struct _LIBCPP_TEMPLATE_VIS char_traits;
          |                             ^

`Key_string` is defined as `std::basic_string<unsigned char>`, which is
no longer possible. So redefine it as a `std::vector<unsigned char>`
instead.

This requires only a few small adjustments in other places: replacing
the `length()` method with the equivalent `size()` method, and adjusting
the arguments for the `assign()` method, which for `std::vector` takes a
begin and end iterator, instead of a begin iterator and a size.

Another issue is that clang 19 now implements CWG 96 [2], which requires
a template argument list after a 'template' keyword, resulting in errors
similar to:

    /wrkdirs/usr/ports/databases/mysql84-client/work/mysql-8.4.2/libs/mysql/serialization/archive.h:84:43:
error: a template argument list is expected after a name prefixed by the
template keyword [-Wmissing-template-arg-list-after-template-kw]
       84 |     return Archive_derived_type::template
get_size(std::forward<Type>(arg));
          |                                           ^
    /wrkdirs/usr/ports/databases/mysql84-client/work/mysql-8.4.2/libs/mysql/serialization/archive.h:91:43:
error: a template argument list is expected after a name prefixed by the
template keyword [-Wmissing-template-arg-list-after-template-kw]
       91 |     return Archive_derived_type::template
get_size_written();
          |                                           ^

This requires a number of adjustments to various template invocations.

[1] https://libcxx.llvm.org/ReleaseNotes/19.html#deprecations-and-removals
[2] https://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#96

PR:	280695
Sponsored by:	Netzkommune GmbH

1 files changed, 11 insertions, 0 deletions

diff --git a/databases/mysql84-server/files/patch-sql_binlog__ostream.cc b/databases/mysql84-server/files/patch-sql_binlog__ostream.cc
new file mode 100644
index 000000000000..1bcf252da064
--- /dev/null
+++ b/databases/mysql84-server/files/patch-sql_binlog__ostream.cc
@@ -0,0 +1,11 @@
+--- sql/binlog_ostream.cc.orig	2024-07-12 19:20:22 UTC
++++ sql/binlog_ostream.cc
+@@ -240,7 +240,7 @@ bool IO_CACHE_binlog_cache_storage::setup_ciphers_pass
+ 
+   /* Generate password, it is a random string. */
+   if (my_rand_buffer(password, sizeof(password))) return true;
+-  password_str.append(password, sizeof(password));
++  password_str.insert(password_str.end(), password, password + sizeof(password));
+ 
+   m_io_cache.m_encryptor->close();
+   m_io_cache.m_decryptor->close();