rapidcheck: refactor postInstall to install all extras

[tsmanner]

RapidCheck's extras were not accessible through the package, with the exception of boost_test, which was being copied directly into the core include directory. RapidTest's documentation for that module says to add the extras/boost_test/include directory to your include path, but the nixpkgs derivation for it puts the file in $out/include/rapidtest.

This support is available through the extras/boost_test module. You can either directly add the extras/boost_test/include directory to your include path or link against the rapidcheck_boost_test target in your CMakeLists.txt. You can then simply #include <rapidcheck/boost_test.h>. Note that rapidcheck/boost_test.h needs to be included after any Boost Test headers.

This commit replaces the copy of that one header with an rsync of all files, except CMakeLists.txts, from $src/extras into $out/extras so that the output path matches what the rapidtest documentation expects. Accessing all extras is now possible by adding "${pkgs.rapidtest}/extras/<extra>/include" to your list of include paths.

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS linux)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Determined the impact on package closure size (by running nix path-info -S before and after)
• Ensured that relevant documentation is up to date
• Fits CONTRIBUTING.md.

[tsmanner]

I haven't done any cross platform testing of this, only confirmed that it works in WSL Debian with gcc 9.3.0.

One thing that isn't clear to me yet is whether or not the boost and gmock cpp files are compiled as part of the normal build, or if they'll need to get their own derivations to get them optionally included in the rapidtest.a that is built by default.

[SuperSandro2000]

Can you please use mv or cp?

[tsmanner]

I originally had tried using cp, but you can't filter the files being copied. Considering that it already depends on cmake I was thinking that a dependency on rsync at build time would be preferable to having installed the extras includes with the CMakeLists.txt files still lying around in there. The thing I had tried was a recursive cp followed by an rm **/CMakeLists.txt, but the destination files were read only, so I switched. If that approach would work by changing the file permissions in $out before doing the rm, then I'm happy to do that.

I played around with builtins.filterSource as well, but it isn't allowed to refer to store paths, so I was left wondering if there was a way to use a nix function to filter that directory, but wasn't sure what to try.

[tsmanner]

I tried with the chmod +w and rm for the CMakeLists.txt files and it is producing the same result as the rsync, just in a more roundabout way.

[SuperSandro2000]

It is preferable to only use rsync if there is no other way. 4 Lines bash instead is fine for me.

[SuperSandro2000]

Result of nixpkgs-review pr 106376 run on x86_64-darwin 1

1 package built:

• rapidcheck

[SuperSandro2000]

Result of nixpkgs-review pr 106376 run on x86_64-linux 1

1 package built:

• rapidcheck