cmake: workaround for MinGW windres
cmake: use findGit.cmake, which was available in cmake 2.8.8, our min version

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extra : amend_source : 43b74ef5d2926bf9a8f55072018706fa9818ac7c
cmake: simplify version detection, use single set of variables
cmake: be quiet about missing optional packages
threading: fix compile when XP support is enabled
weightp: pad width passed to weight_pp(), it requires 16byte alignment

--HG--
extra : amend_source : 68f2a5eb897f93bed9e8d041dc4441f26be3df79
weightp: add assert to protect assembly limitiation