The xine_xmalloc() function is going to be deprecated, as its
behaviour is rarely needed as such, and it's thus misused.

With this, almost all uses of xine_xmalloc() with static size (for
instance the value returned by sizeof()) or with a size that is
guaranteed not to be zero (like strlen()+1) are replaced with calls to
either calloc(1, ...) or malloc().

malloc() is used whenever the allocated memory is going to be
immediately overwritten, while calloc() is used in every other case,
as it sets the whole memory area to zero.

--HG--
extra : transplant_source : %8F%98%EC%02%1E%83%F0s%06X%83C%205Y%80%B12%CC%E1

- Allow visible region updates.
- Resize OSD at drawing time.

--HG--
extra : transplant_source : %17%ECZ%D0j%2C%BC%06%7CO%3A%F0%C7u%A3%86%DE%8Bb%D3

--HG--
extra : transplant_source : %E0%D0%C5%8B%BEU%DD%24%5D7%1F%ADV%AD%EB%23%CBU%80%EB

For contributed code, leave whatever the version we last synced for is using
to make simpler future syncs.

Only build-tested due to lack of sample data.

xine_spudvb_decoder.c has hardcoded frame size (720x576).
While this is fine for most dvb channels, some channels have smaller frame
size (e.g. 544x576) but the dvb subs bitmaps are however still 720 width.
In such case, some right aligned subs appear truncated.
This patch adds a (very basic) function to downscale subs to fit frame width.

When leaving xine playing DVB with subtitles for a long period of time,
I noticed a gradual increase in memory use, caused by it creating more
and more timeout threads. In addition, the existing thread was not safe
w.r.t destruction of the decoder, and would occasionally segfault xine.

Further, EN 300 743 states that the timeout should be sent by the
broadcaster; the existing thread had a constant 6 second timeout,
whereas (e.g.) BBC NEWS 24 subtitles are broadcast with a 15 second
timeout. In theory, this could result in subtitles being hidden in error.

This rework changes the thread to pick up a timeout set by
draw_subtitles; in addition, it uses pthread condition variables to
avoid any need to kill and recreate the thread.