Add warning flags to the DEBUG_CFLAGS too.

All the initialisation functions returning a new object instance that
was allocated through malloc() or calloc() can get the malloc
attribute so that the compiler can optimise their call.

Use the proper function for common memory operations (memset() for
zeroing, memcpy() for copying, memmove() for moving), instead of
looping through arrays.

By extension, remove loops to reset arrays when they were allocated
with calloc() and thus already zeroed.

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

--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.

According to bug 1773769, this breaks foo->open().
The fix (as used in Ville Skyttä's patch, which doesn't cover all cases) is
to replace this with (foo->open)().

This patch was generated using
sed -i -re 's/(([[:alnum:]_]+(->|\.))+open) ?\(/(\1) (/' `grep '[>.]open \?(' include -rIl`
One change (in a comment) is not committed.

The cause was that the resampling code was using only the samples in the buffer
but not really handling the transition between two buffers (which it would
handle completely independently). The new code remembers the last sample from
the previous buffer and uses it in the resampling. We therefore end up one
sample behind and without the clicks.

Some plugins may have been missed due to them not being built here.

Two of the modified files are headers, but each contains definitions as well as
declarations and is only ever used once.