fix Point ambiguity on Mac with Carbon
Merge branch 'master' of https://github.com/avilleret/pix_opencv
Merge branch 'master' of https://github.com/avilleret/pix_opencv
build only for i386 on Mac OS

for now, and due to a QuickTime issue, there is no way to build Gem for x64  arch on Mac OS
thus, there is no reason to build pix_opencv for x64 too...
script to embed needed OpenCV dylib