Signed-off-by: Hugo Beauzée-Luyssen <hugo@beauzee.fr>

The buffer size can be bigger than valid data size.

The build-dir plugin cache is incomplete and contains wrong paths.

The initial set of recognized content types is based on existing
forced psz_demux values. It is likely better not to add entries unless
detection of the file format is known to be difficult/impossible.

The input thread already takes care of this once for both access_demux
and demux.

macosx: fix runtime exception when loading the simple prefs with the Punjabi locale active (closes #15106)

Previously, "" would be used, leading to nonsensical results in those
stream filters that actually need a URL.

cachegen: remove force option and always reset the cache when the helper tool is executed (refs #14519)

plugin cache: do not re-write the cache file unless explicitly requested by the user (closes #14519)