configure: Support cygwin64
x86: Faster AVX2 pixel_sad_x3 and pixel_sad_x4
x86: SSSE3 implementation of pixel_sad_x3 and pixel_sad_x4
Transparent hugepage support

Combine frame and mb data mallocs into a single large malloc.
Additionally, on Linux systems with hugepage support, ask for hugepages on
large mallocs.

This gives a small performance improvement (~0.2-0.9%) on systems without
hugepage support, as well as a small memory footprint reduction.

On recent Linux kernels with hugepage support enabled (set to madvise or
always), it improves performance up to 4% at the cost of about 7-12% more
memory usage on typical settings..

It may help even more on Haswell and other recent CPUs with improved 2MB page
support in hardware.
AVC-Intra support

This format has been reverse engineered and x264's output has almost exactly
the same bitstream as Panasonic cameras and encoders produce. It therefore does
not comply with SMPTE RP2027 since Panasonic themselves do not comply with
their own specification. It has been tested in Avid, Premiere, Edius and
Quantel.

Parts of this patch were written by Jason Garrett-Glaser and some reverse
engineering was done by Joseph Artsimovich.
Windows Unicode support

Windows, unlike most other operating systems, uses UTF-16 for Unicode strings while x264 is designed for UTF-8.

This patch does the following in order to handle things like Unicode filenames:
* Keep strings internally as UTF-8.
* Retrieve the CLI command line as UTF-16 and convert it to UTF-8.
* Always use Unicode versions of Windows API functions and convert strings to UTF-16 when calling them.
* Attempt to use legacy 8.3 short filenames for external libraries without Unicode support.
Fix GPAC support on Windows
Fix masked access violation in KERNEL32

Caused crashes under gdb in Windows and might cause other unknown problems.
Workaround for FFMS indexing bug

If FFMS_ReadIndex is used with an empty index file it gets stuck in an infinite loop instead of returning NULL
like it's supposed to do on failure. Explicitly check if the file is empty before calling it as a workaround.
Fix INSTALL in configure for Solaris systems
Fix possible crashes in resize and crop filters with high bitdepth input
Fix compilation of shared library for Windows with original MinGW toolchain
Fix compilation in case of HAVE_LOG2F check fails spuriously