This commit contains all the tweaks which were missing in initial patch
re-integration from the standalone Cycles repository.
This commit also contains an utility cmake macro to help linking targets
with different libraries for release/debug builds, the name currently is
target_link_libraries_decoupled
it gets a target and list of libraries and makes sure debug builds are
using libraries with "_d" suffix.
After all this changes it'll hopefully be easier to interchange patches
between blender and standalone repositories, because they're now quite
identical.
* 32 bit GCC builds now have the SSE BVH optimizations turned off, but still
compile with SSE flags for better performance.
* White color when rendering on Windows seems to have been unrelated to SSE,
rather it was a graphics driver not supporting half float textures, added a
check for that now.
