Fix pixel_ssim_end4 asm function for x86_64 systems
opencl: Check return value of fread()

common/opencl.c:138:10: warning: ignoring return value of 'fread', declared with attribute warn_unused_result [-Wunused-result]
build: Set all ASFLAGS from within configure

This is how all other toolchain flags are handled.
configure: Don't check for libavcore

libavcore was a never-released bad idea with a short lifespan.
Delete all SPARC optimizations

SPARC has been obsolete for a long time and makes little sense as a
H.264 encoding platform.

Also update authors file.
build: Add dependencies on x86inc.asm/x86util.asm for all .asm files

This is a little bit overzealous, but errs on the side of caution.
Generating full dependency information is also possible, but slightly
slows down the build as YASM cannot do it as a sideeffect of compilation.
configure: Drop workaround for obsolete gcc 4.2 on ARM
build: Simplify phony target declaration with wildcards

Also add etags to list of phony targets.
build: Replace cltostr.pl by a shell script

This avoids a dependency on Perl to build OpenCL support.
configure: Add -Wno-maybe-uninitialized to CFLAGS

The warnings generated by -Wmaybe-uninitialized are mostly spurious.
MSVS 2013 Update 2 support

The first MSVS compiler C99 compliant enough to build x264.
Use `CC=cl ./configure` to compile with it.
Fix frame-packing==5 with some decoders

The spec mandates that frame-packing==5 requires the SEI on every frame that
begins a view sequence (i.e. the input frames L0-R0-L1-R1 have 4 view sequences,
but if reordered by the encoder to L0-L1-R0-R1 there are now 2 view sequences).
For simplicity, we write the SEI on every frame.

This fixes frame-packing==5 3D playback on some decoders (PlayStation 3, Sony
W8 series, possibly others).
Remove meaningless use of abs()
mp4_lsmash: Use new I/O API instead of deprecated one.