Merge branch 'master' into iosevka-buildnpmpackage

/pkgs/development/ruby-modules      @marsam

# Rust

/pkgs/development/compilers/rust @Mic92 @LnL7 @zowoq

/pkgs/development/compilers/rust @Mic92 @LnL7 @zowoq @winterqt @figsoda

/pkgs/build-support/rust @zowoq @winterqt @figsoda

/doc/languages-frameworks/rust.section.md @zowoq @winterqt @figsoda

# C compilers

/pkgs/development/compilers/gcc @matthewbauer

# Testers {#chap-testers}

This chapter describes several testing builders which are available in the <literal>testers</literal> namespace.

## `hasPkgConfigModule` {#tester-hasPkgConfigModule}

Checks whether a package exposes a certain `pkg-config` module.

Example:

```nix

passthru.tests.pkg-config = testers.hasPkgConfigModule {

  package = finalAttrs.finalPackage;

  moduleName = "libfoo";

}

```

## `testVersion` {#tester-testVersion}

Checks the command output contains the specified version

As per [RFC 0072](https://github.com/NixOS/rfcs/pull/72), all new documentation content should be written in [CommonMark](https://commonmark.org/) Markdown dialect.

Additional syntax extensions are available, though not all extensions can be used in NixOS option documentation. The following extensions are currently used:

Additional syntax extensions are available, all of which can be used in NixOS option documentation. The following extensions are currently used:

- []{#ssec-contributing-markup-anchors}

  Explicitly defined **anchors** on headings, to allow linking to sections. These should be always used, to ensure the anchors can be linked even when the heading text changes, and to prevent conflicts between [automatically assigned identifiers](https://github.com/jgm/commonmark-hs/blob/master/commonmark-extensions/test/auto_identifiers.md).

  ## Syntax {#sec-contributing-markup}

  ```

  ::: {.note}

  NixOS option documentation does not support headings in general.

  :::

- []{#ssec-contributing-markup-anchors-inline}

  **Inline anchors**, which allow linking arbitrary place in the text (e.g. individual list items, sentences…).

  This syntax is taken from [MyST](https://myst-parser.readthedocs.io/en/latest/syntax/syntax.html#roles-an-in-line-extension-point). Though, the feature originates from [reStructuredText](https://www.sphinx-doc.org/en/master/usage/restructuredtext/roles.html#role-manpage) with slightly different syntax.

  ::: {.note}

  Inline roles are available for option documentation.

  :::

- []{#ssec-contributing-markup-admonitions}

  **Admonitions**, set off from the text to bring attention to something.

    - [`tip`](https://tdg.docbook.org/tdg/5.0/tip.html)

    - [`warning`](https://tdg.docbook.org/tdg/5.0/warning.html)

  ::: {.note}

  Admonitions are available for option documentation.

  :::

- []{#ssec-contributing-markup-definition-lists}

  [**Definition lists**](https://github.com/jgm/commonmark-hs/blob/master/commonmark-extensions/test/definition_lists.md), for defining a group of terms:

 <xi:include href="octave.section.xml" />

 <xi:include href="perl.section.xml" />

 <xi:include href="php.section.xml" />

 <xi:include href="pkg-config.section.xml" />

 <xi:include href="python.section.xml" />

 <xi:include href="qt.section.xml" />

 <xi:include href="r.section.xml" />

# pkg-config {#sec-pkg-config}

*pkg-config* is a unified interface for declaring and querying built C/C++ libraries.

Nixpkgs provides a couple of facilities for working with this tool.

 - A [setup hook](#setup-hook-pkg-config) bundled with in the `pkg-config` package, to bring a derivation's declared build inputs into the environment.

 - The [`validatePkgConfig` setup hook](https://nixos.org/manual/nixpkgs/stable/#validatepkgconfig), for packages that provide pkg-config modules.

 - The `defaultPkgConfigPackages` package set: a set of aliases, named after the modules they provide. This is meant to be used by language-to-nix integrations. Hand-written packages should use the normal Nixpkgs attribute name instead.