Signed-off-by: Diego Biurrun <diego@biurrun.de>

This is more consistent with the way we handle C #includes and
it simplifies the build system.

This is necessary to allow refactoring some x86util macros with cpuflags.

Add support for all x86-64 registers
Prefer caller-saved register over callee-saved on WIN64
Support up to 15 function arguments

Also (by Ronald S. Bultje)
Fix up our asm to work with new x86inc.asm.
Signed-off-by: Ronald S. Bultje <rsbultje@gmail.com>
Signed-off-by: Justin Ruggles <justin.ruggles@gmail.com>

Fixes pre-processing with latest versions of nasm.

They were introduced in an earlier commit that introduced use of named
arguments. One cause was a typo, a second cause appears to be a bug in
x264asm that I work around by not using named arguments.

"dstw" can collide with the word-version of the "dst" argument, causing
all kind of weird stuff down the pipe.

Most of the function had been converted before, but I forgot this
particular location.

This allows combining multiple conditionals in a single statement.

scale.asm keeps horizontal scaling functions, whereas output.asm gets
the vertical scaling/output functions.