compat.h : Simplify definition of FLAC__U64L.

Patch-from: lvqcl <lvqcl.mail@gmail.com>
Add FLAC__ prefix to precompute_partition_info_sums....

Most non-static functions have FLAC__ prefix, but they were missing
from the precompute_partition_info_sums_* functions.

Patch-from: lvqcl <lvqcl.mail@gmail.com>
libFLAC/ia32/lpc_asm.nasm : Match calls and returns.

According to Agner Fog, "...you must make sure that all calls
are matched with returns. Never jump out of a subroutine without
a return and never use a return as an indirect jump."

(see paragraph 3.15 in microarchitecture.pdf and
examples 3.5a and 3.5b in optimizing_assembly.pdf)

Patch-from: lvqcl <lvqcl.mail@gmail.com>
libFLAC : Add asm versions for two _wide() functions.

GCC generates slow ia32 code for FLAC__lpc_restore_signal_wide() and
FLAC__lpc_compute_residual_from_qlp_coefficients_wide() so 24-bit
encoding/decoding is slower for GCC compile than for MSVS or ICC
compile. This patch adds ia32 asm versions of these functions.

Patch-from: lvqcl <lvqcl.mail@gmail.com>
lpc_asm.nasm : More 'mov cl' -> 'mov ecx' fixes.

According to Agner Fog in optimizing_assembly.pdf:

  "... write to a partial register may result in false dependencies
   between instructions, so it is better to avoid it."

Patch-from: lvqcl <lvqcl.mail@gmail.com>