Modified avs4x264

The code is based on on AVS-input
from x264 (http://www.videolan.org/developers/x264.html).

You can use this software to encode videos using the 32-bit version
of Avisynth with the 64-bit version of x264 under Windows.
The x264 executable needs to be named x264_64.exe and placed in the
same folder as this program. Otherwise use --x264-binary "x264_path"
or -L "x264_path" to define the pach of x264 binary.
Example:
avs4x264mod.exe --x264-binary "C:\x264_64-abc.exe" -o out.264 in.avs

avs4x264mod v0.6:
Modified by 06_taro ( [email protected] ).
Modifications: 
-- When x264's parameter "input-depth" is set and is not equal to 8, 
   divide "width" by 2. This makes faked 16-bit avs output, i.e.,
   MSB and LSB field interleaved clip, be treated correctly by x264.
   If "input-depth" is not defined or equals to 8, avs4x264mod acts
   in the same way as original avs4x264.
   Example:
   avs4x264mod.exe --input-depth 16 "C:\x264.exe" -out o.264 in.avs
-- Print full command-line piped out to x264_64.exe to screen,
   prefixed by "avs4x264 [info]:".
-- Make x264_64.exe path changeable. The path of x264 binary can be
   set by --x264-binary "x264_path" or -L "x264_path".
   Use "x264_64" by default if
   --x264-binary is not set.
   Example:
   avs4x264mod.exe --x264-binary "C:\x264.exe" -o out.264 in.avs
   avs4x264mod.exe -L "C:\x264.exe" -o out.264 in.avs
-- Directly output i422/i444 with AviSynth 2.6 csp YV16/YV24.
-- Improve capability with more styles of parameters in x264.
   E.g., --tcfile-in="timecode.txt", --input-depth=16,
         --x264-binary="x264", -L=x264 and -Lx264.
-- Do not add --input-res/--fps/--frames if already defined.
-- Correct number of frames to be handled when --frames is defined.

Compiling:
with gcc 4.6.x:
gcc avs4x264mod.c -s -Ofast -oavs4x264mod -Wl,--large-address-aware
with old versions:
gcc avs4x264mod.c -s -O3 -ffast-math -oavs4x264mod -Wl,--large-address-aware