gplugin/gplugin

Don't bother looking for libperl on FreeBSD as it's there if the perl executable is installed.

2020-11-20, Gary Kramlich
b9265f30d267
Don't bother looking for libperl on FreeBSD as it's there if the perl executable is installed.

Testing Done:
Tested on debian with and without libperl-dev installed as well as FreeBSD with perl installed.

Reviewed at https://reviews.imfreedom.org/r/246/
There are a few notes about building on OSX.
First off, building has *ONLY* been tested against homebrew. If you want to
support fink or macports, please let me know and I will merge your pull
request.
Currently there is no known way to build the Perl loader on MacOS. So you
**MUST** run meson with `-Dperl5=false`.
## Lua
For the Lua loader to work, you need to install `lgi` from luarocks either
systemwide or to a virtual environment created by LuaDist, vert, or something
along those lines, then you just need to run `luarocks install lgi`.
## Python3
If you're using homebrew, you need to install `pygobject3`.