Re: Updating libpqxx to 8.0.1

Since I wanted to test sqlsmith against the new libpqxx, I went ahead
and packaged it. Thanks for the analysis, that helped!

> * libpqxx has released a new major version
> * Requires compiling with at least C++20

I had to "export DEB_CXXFLAGS_MAINT_APPEND = -std=gnu++20" to make it
work but the rest didn't require extra poking.

> * C++20 was not stable until GCC 16
> * The documentation for C++ Standards Support in GCC indicates that
> most/several C++20 features are supported in GCC 11+

> * Debian bookworm gcc 12

Bookworm fails because its libstc++-12-dev is missing the "format" header.

(Bullseye fails because libpqxx wants autoconf 2.71. I did not
investigate further since bookworm already fails.)

> * Ubuntu jammy gcc 11

It looks like jammy's autoconf-archive package is too old:

error: invalid first argument `20' to AX_CXX_COMPILE_STDCXX

But let's ignore that, it's EOL next year.

> * Ubuntu noble gcc 13

That worked.

Christoph