Add a pq-src crate for a bundled feature flag

[weiznich]

No description provided.

[weiznich]

I personally have only access to a linux development environment. That makes it hard to fix the remaining issues on windows/macos. If you are a user of diesel or pq-sys and use one of these platforms consider helping figuring out these issues.

[fsasieta]

While I can't guarantee an allotted time per week to support this, I'm interested in contributing. I primarily develop on my local environment using a MacOS platform (ARM Chip). Would be happy to contribute if there are guidelines to doing this. I've skimmed over the diesel contributing guidelines, but have never contributed to diesel

[weiznich]

@fsasieta Thanks for your interest to contribute. There is no need to have guarantee any amount of time for this, as at least for me that's a free time project. For this specific change I'm interested in the following information:

• Build output of libpq on your platform (so which files are exactly compiled, etc). This likely requires cloning the postgres source, checking out the 16.0 release tag, configuring the build and building libpq by executing make in src/interfaces/libpq (and recording the output of that)
• Maybe: What needs to be adjusted in the build script to match this output. So essentially what needs to be changed so that cargo build in the pq-src directory works on your system. The linked build script should essentially mirror the make file generated by ./configure as much as possible.

I'm happy to help with as much information as I can if you hit a road block or if there are any other question.

[alcroito]

Attaching build logs on an intel mac, I hope it helps.
Commands were:

clone and checkout REL_16_0 tag
export PKG_CONFIG_PATH="/usr/local/opt/icu4c/lib/pkgconfig"
mkdir build && cd build
../configure --prefix=$PWD/../installed &> configure.txt
make -j8 &> build.txt
make install &> install.txt

pq_build_logs_intel_mac.zip

Looking at homebrew recipe, they pass a few more flags when building but not sure if they are relevant here
https://github.com/Homebrew/homebrew-core/blob/master/Formula/lib/libpq.rb#L43

[weiznich]

Thanks for providing these logs ❤️ . I will see if they help an report back with results in the next days

[weiznich]

@alcroito Thanks again for your help. I've merged this PR as it's now ready to be used 🥳