opencv 2.4.2: fix pkgconfig support

The fix from meta-oe master branch for opencv 2.4.3 couldn't be safely backported, so recreate it for 2.4.2

Signed-off-by: Koen Kooi <koen@dominion.thruhere.net>
opencv: switch to out-of-tree builds

This eliminates a few warnings from the configure step and makes sense in general.

Signed-off-by: Koen Kooi <koen@dominion.thruhere.net>
opencv: enable SSE1/2/3 and SSSE3 when finding '-msse3' in TARGET_CC_ARCH

Signed-off-by: Koen Kooi <koen@dominion.thruhere.net>
opencv: backport RPATH fix for meta-oe master branch

Signed-off-by: Koen Kooi <koen@dominion.thruhere.net>