libs/libx264: Update to 20190324 and rework Makefile

libs/libx264: Update to 20190324 and rework Makefile

* Update (lib)x264 to 20190324
* Stop using GNU Autotools and use libx264's own
  configuration facility
* Drop hardcoded CFLAGS, x264 will handle those fine on its own
  This will override toolchain optimizaion and set -O3
  irregardless of setting.
* Rework LTO and ASM optmization selection to make it more
  compact and readable. This drops optimization for x86 32-bit
  which is being deprecated in favour of x86_64 in general and
  the very few systems still in use that doesn't support 64-bit
  are too slow to be usable anyway.
* Import patches to fix compilation on ARM and x86 (32-bit)
  from OpenEmbedded
* Minor style fixes to Makefile

Source: http://cgit.openembedded.org/openembedded-core/tree/meta/recipes-multimedia/x264/x264

Signed-off-by: Daniel Engberg <daniel.engberg.lists@pyret.net>