deps.ffmpeg: Enable PDBs for FFmpeg builds on Windows

[RytoEX]

Description

Enable PDBs for FFmpeg builds on Windows if the Configuration is set to Debug or RelWithDebInfo.

Motivation and Context

Having PDBs for FFmpeg can be useful for debugging crashes. This was one of the original goals of moving the FFmpeg builds to be natively compiled.

How Has This Been Tested?

Tested locally about a year ago. Should probably be retested.

Types of changes

• Tweak (non-breaking change to improve existing functionality)

Checklist:

• My code has been run through clang-format.
• I have read the contributing document.
• My code is not on the master branch.
• The code has been tested.
• All commit messages are properly formatted and commits squashed where appropriate.
• I have included updates to all appropriate documentation.

[RytoEX]

Just confirming that the recent push still creates PDBs for the DLLs:

Executables are suffixed for some reason:

The PDBs are not currently copied/installed to the install dir.

[RytoEX]

Apparently, I had forgotten to actually push the changes. The PDBs are still not actually part of any final artifacts, as I have to figure out where those are installed/copied.

[PatTheMav]

Looking at my own code from the distance of a few years makes me want to refactor the entire build system for obs-deps, but that's a different story.. 😅

[RytoEX]

Following up: PDBs are now manually copied to the install dir and are made part of the ffmpeg-windows-arm64 and ffmpeg-windows-x64 artifacts instead of being in separate artifacts. May change this later to split them out, but they add fairly little to the existing archive sizes (4~6 MB).