contrib: harfbuzz: disable icu

icu-config is not suited for cross-compilation
demux: ogg: fix use after free seekpoints.

Also cleans seekpoints between tracks
demux: ogg: add preparsing of headers (fix #6691)
demux: ogg: delay ES creation for preparsing.

Prevents creating ES & decoders just for playlist preparsing.
demux: add missing default handler for GET_SIGNAL
demux: ogg: do PCR handling on stream boundary
demux: ogg: don't probe length again with chained streams
Merge remote-tracking branch: upstream/master