OpenCL: Fix for the fork/MPI "poor man's multi-device" stuff, so formats
that support multiple devices natively does not get screwed up.
Export get_platform_id() from common-opencl.
Fix OSX build targets for CUDA for Xcode 5.0 and CUDA 5.

For search engine reference, the problem was this:
clang: error: unsupported option '-dumpspecs'
NVCC tweaks (mostly comments, but add -fmad=true) in Makefile.
pass_gen.pl: Only require libs that are actually needed for specific run.
Fix an obscure bug in mscash where an overlong key would truncate
to 28 instead of 27 in UTF-8 mode. NT already had a fix for it so
unify the code for them.
Cosmetical fixes in common-opencl.c.
Protect a CUDA macro from being expanded to something not intended.
I'm not sure there was a problem, just saw the dangerous definiton.
Change malloc() to mem_alloc() in a bunch of formats. The latter sits
in memory.c and has error checking.
Align fix to CUDA md5crypt.
Update CHANGES-jumbo.git and CREDITS-jumbo.
Update CHANGES-jumbo.git (the unstable-jumbo part of it).