cmake: pick the old policy for MACOSX_RPATH (only applicable for cmake 3.0)
frameencoder: prevent deadlock in non-wpp mode
xp: fix header guards for XP support, fixes MinGW build

If no _WIN32_WINNT version is specified, MinGW defaults to XP SP3.  Our include
guards were checking for <= XP instead of checking for any version before Vista
which was the version that introduced native CONDITION_VARIABLE support

--HG--
extra : amend_source : 787e69524a622a4f291215d72430adabe7a097a4
dither: port dither related functions from x264
cli: add cli option for dither
primitives: added C primitives for upShift/downShift of input pixels
asm: code for input pixel upShift/downShift
testbench: code for testing input pixel upShift/downShift primitives
remove macro NEW_CALCRECON
slicetype: do not assume frames[] array has been initialized

slicetypeAnalyse() may not have been called, so use picture list[] instead