Re: Build issue with postgresql 17 undefined reference to `pg_encoding_to_char' and `pg_char_to_encoding'

Hi Mikael,

> This is for compiling a c++ application that uses libpq with the -static flag, the server compiles fine.

OK. I couldn't quite do this because the only Linux machine I have at
the moment runs Raspbian and there doesn't seem to be a static glibc
available for it. But here is how to achieve what you want *in
theory*.

First compile Postgres from the source code, for instance (change the
flags as needed, you probably want a release build):

```
# sudo apt install clang-16
# git clean -dfx
CFLAGS="-static" meson setup --buildtype debug -Dicu=disabled
-Dldap=disabled -Dreadline=disabled -Dzlib=disabled -Dlz4=disabled
-Dprefix=/home/eax/pginstall build
ninja -C build
```

I recommend using Meson and Ninja. Autotools and Make are still
supported but are slow and probably will be gone in a few years. The
"ninja -C build" steps fail for me with various errors about the need
for static glibc but I think it should work on other distributions and
architectures.

Next install Postgres. I use a script for this [1]:

```
~/pgscripts/single-install-meson.sh
```

Change the script as needed - you probably don't need pg_ctl,
createdb, etc for your task.

Now in order to compile and execute your C++ program:

```
export PRFX=/home/eax/pginstall
g++ -g -Wall -o test_libpq -I$PRFX/include
-L$PRFX/lib/aarch64-linux-gnu/ test_libpq.cpp -lpq -static
LD_LIBRARY_PATH=$PRFX/lib/aarch64-linux-gnu/ ./test_libpq
```

This being said I don't recall seeing anything about the support of
static linking of libpq in the documentation [2]. To my knowledge this
is not officially supported / tested / maintained which means you and
your colleagues are on your own with the -static flag. Since you are
already using Docker, perhaps the easiest thing to do would be to back
the application and all its dependencies (dynamically linked) in a
Docker container.

Good luck.

[1]: https://github.com/afiskon/pgscripts/
[2]: https://www.postgresql.org/docs/current/libpq.html

--
Best regards,
Aleksander Alekseev