Remove old/broken PPC/Altivec code.

* Removes FLAC__lpc_restore_signal_asm_ppc_altivec_16*
  from lpc.h and stream_decoder.c
* Removes PPC-specific code from cpu.c and cpu.h
* Removes PPC stuff from libFLAC/Makefile.lite and build/*.mk
* Removes as/gas/PPC-specific stuff from configure.ac and
  libFLAC/Makefile.am*
* Removes libFLAC/ppc folder and remove "src/libFLAC/ppc*/Makefile"
  lines from configure.ac

Patch-from: lvqcl <lvqcl.mail@gmail.com>
cpu.h : Only define FLAC__SSE_SUPPORTED if FLAC__HAS_X86INTRIN is set.

Patch-from: lvqcl <lvqcl.mail@gmail.com>
fixed_intrin_sse[23].c : Simplify  XMM -> int64 conversion.

Patch-from: lvqcl <lvqcl.mail@gmail.com>
vorbiscomment.c : Do not write empty vorbiscomment fields.

That is, only write vorbis comment fields if they are non-empty.

Patch-from: Janne Hyvärinen <cse@sci.fi>
Minor clean up of win_utf8_io.

Patch-from: lvqcl <lvqcl.mail@gmail.com>
win_utf8_io.c: Use fputws instead of fwprintf.

Signed-off-by: Erik de Castro Lopo <erikd@mega-nerd.com>
stream_encoder_intrin_sse[23].c : Optimize of int32 -> uint64 conversion.

Optimizes int32 -> uint64 conversion by doing zero extension (int32 ->
uint32 -> uint64) instead of sign extension (int32 -> int64 -> uint64).

Patch-from: lvqcl <lvqcl.mail@gmail.com>
fixed_intrin_sse[23].c : Add new, simpler SSE code.

It's simpler but not faster so it is disabled by default. Maybe it
will be faster on newer CPUs though..

Patch-from: lvqcl <lvqcl.mail@gmail.com>
lpc_intrin* : Remove unused code.

Which in turn simplifies FLAC__lpc_restore_signal_16_intrin_sse2()
function.

Patch-from: lvqcl <lvqcl.mail@gmail.com>
lpc_intrin_sse41.c : Optimize decoding 24 bit files on 32 bit platforms.

Patch-from: lvqcl <lvqcl.mail@gmail.com>
flac/utils.c : Fix calculation of a tag length.

Patch-from: lvqcl <lvqcl.mail@gmail.com>
Add partial_tukey and punchout_tukey apodization functions

Adds two new apodization functions that seem to perform better than
the apodization functions currently in the codebase and fixes three
existing windows as well.

Its important to note that this patch only affects the encoder stage
that evaluates various possible predictors. Audio encoded with these
new windows will still decode with existing legacy decoders.

= Theory =
These functions are used to window the  audio data at the predictor
stage. These news functions enable the use of only part of the signal
to generate a predictor. This helps  because short transients can
introduce noise into the predictor. The  predictor becomes very good
at prediciting one part of the  signal, instead of mediocre for the
whole block.

Signed-off-by: Erik de Castro Lopo <erikd@mega-nerd.com>
win_utf8_io.c : Comment only.

Explains why flac is currently incompatible with extended-length paths.

Patch-from: lvqcl <lvqcl.mail@gmail.com>
Windows specific vsnprintf fixes.

* Changes flac_snprintf (in src/share/grabbag/snprintf.c) and its copy
  local_snprintf (src/libFLAC/metadata_iterators.c) to be almost sane.

* Adds flac_vsnprintf (src/share/grabbag/snprintf.c) and its copy
  local_vsnprintf (src/share/win_utf8_io/win_utf8_io.c).

* Changes stats_print_info in src/flac/utils.c so it uses flac_vsnprintf
  instead of vsnprintf. This makes return value checking unnecessary.

Patch-from: lvqcl <lvqcl.mail@gmail.com>
libFLAC/window.c : Whitespace.
flac : Add help output for --ignore-chunk-sizes option.

Patch-from: lvqcl <lvqcl.mail@gmail.com>
stream_encoder.c : Give the encoder a larger stdio buffer.

Windows in particular can experience slow encoding speeds on highly
fragmented disks. Using setvbuf to increase the size of the buffer to
10Meg.

This is probably not needed on Linux/Unix, but is very unlikely to
to cause any negative effects.

Patch-from: Janne Hyvärinen <cse@sci.fi>
libFLAC/cpu.c : Refactor for readability.

Patch-from: lvqcl <lvqcl.mail@gmail.com>
metaflac : Fix typo in error message.

Patch-from: Janne Hyvärinen <cse@sci.fi>
Improve malformed vorbiscomment handling.

A few minor tweaks on a patch from Janne Hyvärinen <cse@sci.fi>.

fixup