win32: reduce size of PATH env var + bump ffmpeg to 4.1.3
commit c786776f:
gst-uninstalled: De-dedup before prepending to an env var
Helps us avoid breaching the maximum length limit for env var values
on Windows.
commit d422c2b7:
gst-uninstalled: Try to use short names for env vars on Windows
Try even harder to not hit the maximum length limit for env var values
on Windows. Reduces the size by ~1000 characters on my machine.
commit 6a3a7760:
ffmpeg.wrap: Bump to 4.1.3
Tested on Windows.