gplugin/gplugin

Remove Perl5 support

21 months ago, Gary Kramlich
725422517004
Remove Perl5 support

This was originally added to keep feature parity with purple2, but it has been
a huge pain, there's no solution on macOS, it randomly breaks, and there never
really was a lot of adoption of it in purple2.

Also the IEEE and Stack Overflow surveys from 2022 have Perl ranked between the
20th and 30th most popular programming language so I feel comfortable remove it.

If necessary we can always pull back out of version control and bring it back up
to date.

Testing Done:
Compiled

Reviewed at https://reviews.imfreedom.org/r/1793/
## clang-format
GPlugin uses [clang-format][1] to automatically format code. Version 9 (or
higher) is required. Earlier versions will fail on the options in the
`.clang-format` file.
You can use clang-format in one or more of the following ways:
* Integrate it into your editor. The [clang-format page][1] has examples.
* Use a Mercurial [hook script][2].
* Run `ninja clang-format` from your build directory.
* Worst case, run `clang-format -i SOME_FILE` manually.
### GObject Functions
GObject and GPlugin have functions which take pairs of name/value arguments:
* `g_object_get()`
* `g_object_new()`
* `gplugin_plugin_info_new()`
If code calling one of these functions with such pairs has to be wrapped, the
pairs are easier to read and edit with manual formatting to group the name and
value on the same line (but otherwise following the usual formatting that
clang-format would apply):
```
/* clang-format off */
g_object_get(
G_OBJECT(info),
"name", &name,
"summary", &summary,
NULL);
/* clang-format on */
```
### Debian
Debian and derivatives (e.g. Ubuntu) ship clang-format version 9 in a package
named `clang-format-9`. The package named `clang-format` is currently an
older version. Additionally, the `clang-format-9` package will not place a
`clang-format` in the `$PATH`. Install as follows:
```
sudo apt install clang-format-9
sudo update-alternatives --set clang-format /usr/bin/clang-format-9
```
## convey
GPlugin uses [Convey][3] for CI. You can run the integration tests locally.
To initially setup Convey, which requires Docker:
1. Install Convey. You can use a pre-built binary from [convey's Downloads
page][4]; put that (or a symlink) in your `$PATH` named `convey`.
For now, avoid version 0.14.
2. Install Docker. On Debian systems, use: `sudo apt install docker.io`
3. Add yourself to the `docker` group. Adding yourself to a group does not
add that group to your existing session, so the first time you will need to
get a shell in that group with `newgrp docker` or by rebooting.
To run all of the integration tests, run the "all" metaplan:
```
convey all
```
To run a specific test/platform, run the plan directly:
```
convey alpine-edge-amd64
```
To get a list of metaplans and their plans:
```
convey list metaplans
```
[1]: https://clang.llvm.org/docs/ClangFormat.html
[2]: https://hg.mozilla.org/projects/nss/file/default/coreconf/precommit.clang-format.sh
[3]: https://keep.imfreedom.org/grim/convey
[4]: https://bintray.com/pidgin/releases/convey