Re: gcc 13 warnings

Hi,

> I have committed the change of buildtype to debugoptimized.

There is still a warning previously reported by Melanie:

```
[1391/1944] Compiling C object src/pl/plpgsql/src/plpgsql.so.p/pl_exec.c.o
In file included from ../src/include/access/htup_details.h:22,
from ../src/pl/plpgsql/src/pl_exec.c:21:
In function ‘assign_simple_var’,
inlined from ‘exec_set_found’ at ../src/pl/plpgsql/src/pl_exec.c:8382:2:
../src/include/varatt.h:230:36: warning: array subscript 0 is outside
array bounds of ‘char[0]’ [-Warray-bounds]
230 | (((varattrib_1b_e *) (PTR))->va_tag)
| ^
../src/include/varatt.h:94:12: note: in definition of macro ‘VARTAG_IS_EXPANDED’
94 | (((tag) & ~1) == VARTAG_EXPANDED_RO)
| ^~~
../src/include/varatt.h:284:57: note: in expansion of macro ‘VARTAG_1B_E’
284 | #define VARTAG_EXTERNAL(PTR) VARTAG_1B_E(PTR)
| ^~~~~~~~~~~
../src/include/varatt.h:301:57: note: in expansion of macro ‘VARTAG_EXTERNAL’
301 | (VARATT_IS_EXTERNAL(PTR) &&
!VARTAG_IS_EXPANDED(VARTAG_EXTERNAL(PTR)))
| ^~~~~~~~~~~~~~~
../src/pl/plpgsql/src/pl_exec.c:8570:17: note: in expansion of macro
‘VARATT_IS_EXTERNAL_NON_EXPANDED’
8570 |
VARATT_IS_EXTERNAL_NON_EXPANDED(DatumGetPointer(newvalue)))
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
[1687/1944] Compiling C object
src/test/modules/test_dsa/test_dsa.so.p/test_dsa.c.o^C
ninja: build stopped: interrupted by user.
``

Displayed only for the release builds, e.g.:

```
git clean -dfx
meson setup --buildtype release -DPG_TEST_EXTRA="kerberos ldap ssl"
-Dldap=disabled -Dssl=openssl -Dcassert=true -Dtap_tests=enabled
-Dprefix=/home/eax/pginstall build
ninja -C build
```

Compiler version is:

```
gcc (Debian 12.2.0-14) 12.2.0
```

The overall environment is Raspberry Pi 5 with pretty much default
configuration - Raspbian etc.

How to fix it? Absolutely no idea :)

--
Best regards,
Aleksander Alekseev