First of all, it improves the qt demuxer, ensuring that 24-bit audio is
marked appropriately, and detecting little vs. big endian audio. It also
adjusts the buffer size when audio is 24-bit, ensuring that samples aren't
chopped in half (8192 does not divide evenly into 3 byte samples).

Secondly, in the lpcm decoder, the patch distinguishes between standard
24-bit lpcm (big and little endian) and special DVD-format 24-bit lpcm (see
http://wiki.multimedia.cx/index.php?title=PCM) and now handles both, instead
of only handling the DVD format.

The result is that xine now correctly plays all the 24-bit lpcm samples I
throw at it, whereas before only a few worked.

There was added memory limits checks, which will improve stability when playing
corrupted NSF files.

- use -no-undefined flag only for building shared libraries (libxine, plugins)
- plugins LDFLAGS unification
- move -no-undefined into LDFLAGS_NOUNDEFINED
- attributes.m4 fix

This will reduce logspam with little-endian streams, which Can't Happen anyway.

I have LCPM 24bit DVD.

When I played it on xine, sound was noisy noise. I found that LCPM 24bit
byte stream is _not_ the same as WAVE 24bit byte stream.

(data is lost if PCM frames are splitted in the middle)