Enable fiddle extension also on Windows

[traversaro]

Required by conda-forge/libignition-tools-feedstock#12 (comment) . As the fiddle extentions is using libffi that is found by the custom build script via pkg-config, this PR enables the libffi and pkg-config dependencies also on Windows.

Tests have been added to ensure that the fiddle extention indeed loads fine.

Checklist

• Used a personal fork of the feedstock to propose changes
• Bumped the build number (if the version is unchanged)
• Reset the build number to 0 (if the version changed)
• Re-rendered with the latest conda-smithy (Use the phrase @conda-forge-admin, please rerender in a comment in this PR for automated rerendering)
• Ensured the license file is being packaged.

[conda-forge-linter]

Hi! This is the friendly automated conda-forge-linting service.

I just wanted to let you know that I linted all conda-recipes in your PR (recipe) and found it was in an excellent condition.

[traversaro]

@conda-forge-admin, please rerender

[traversaro]

This was way easier that I expected, but the test seems to pass fine.

[traversaro]

The PR is ready for review @conda-forge/ruby .

[traversaro]

@conda-forge-admin, please rerender

[traversaro]

@conda-forge-admin, please rerender

[github-actions]

Hi! This is the friendly automated conda-forge-webservice.
I tried to rerender for you, but it looks like there was nothing to do.

[traversaro]

The PR is ready for review @conda-forge/ruby @wolfv . This should unblock conda-forge/libignition-tools-feedstock#12 (comment) .

[Tobias-Fischer]

Any chance of merging this in @conda-forge/ruby @wolfv?

[traversaro]

And after all this time, I just realized that I forgot to bump the build number. -_-
Probably I forgot to update the PR after #82 .

[traversaro]

And after all this time, I just realized that I forgot to bump the build number. -_-

New PR in #86 .