livehttp: remove leftover segments if delsegs is on

Also check if i_numsegs is setted as delsegs is tru by default
and we don't want to cause suprises to people creating VOD-stuff.
lua: fix NULL dereference and flawed logic
transcode: fix logic/code when reinitialize filter on channel/rate change

Only check samplerate and physical_channels for now
lua: separate generic and interface-specific net functions
lua: small macro factorization
Revert "opensles: uncomment debug message"

This reverts commit 72999af2315f158128266d6826e15fb2735348f1.

This module seems to work fine, let developers enable this verbose
message again if they wish.
configure: remove legacy Altivec checks - should fix #9757
Audio decoder: output buffered decoded frames on EOF

If EOF happens during buffering, the buffered frames will be flushed
and never played back.
This should only be visible for very short files such as:
http://streams.videolan.org/issues/9195/73ms-VLC-KO.wav

Note, pulse will lose the audio for such short files, alsa and afile work better

Closes: #3152
contrib/gcrypt: fix compilation for iOS
extras/ios: enable gcrypt as we need it for HLS playback