gplugin/gplugin

Python3 has started shipping multiple pc files so we need to check for all of them similar to lua.

2021-07-23, Gary Kramlich
bf9af95cb6d4
Python3 has started shipping multiple pc files so we need to check for all of them similar to lua.

Testing Done:
Ran on debian unstable with python3.10 and python3.9 installed. pygobject doesn't current work with python3.10 according to the test output but python3.9 worked fine.

```
Dependency pygobject-3.0 found: YES 3.38.0 (cached)
Found pkg-config: /usr/bin/pkg-config (0.29.2)
Run-time dependency python-3.10-embed found: YES 3.10
Checking if "Python3 GI" with dependencies glib-2.0, python-3.10-embed, pygobject-3.0 runs: NO (255)
Message: pygobject does not work with python-3.10-embed
Run-time dependency python-3.9-embed found: YES 3.9
Checking if "Python3 GI" with dependencies glib-2.0, python-3.9-embed, pygobject-3.0 runs: YES
```

Reviewed at https://reviews.imfreedom.org/r/832/
# Dependencies
GPlugin depends on the following at a bare minimum:
* glib-2.0 >= 2.40.0
* gobject-introspection, libgirepository1.0-dev
* meson >= 0.42.0
* gettext
* help2man
* a C compiler
A full build (enabled by default) depends on the following:
* gtk-3
* python3-dev, python-gi-dev, python3-gi
* libperl-dev, libglib-perl, libglib-object-introspection-perl
* liblua5.1-0-dev, lua-lgi
* valac
All of these packages and their development headers need to be installed
prior to building GPlugin.
# Building
GPlugin uses [meson](https://mesonbuild.com/) as its build system. As such
compiling is a little bit different than your typical `./configure`, `make`,
`sudo make install`.
Meson requires you to build in a separate directory than your source. As such,
these instructions use a separate build directory.
To compile you need to run the following commands:
```
meson build
cd build
ninja install
```
If you want/need to tweak the build system (to enable/disable certain loaders)
you can do so at any time by using `meson configure` in the build directory.