Check for failure to mark memory as executable (restricted kernels).
Fix handling of redundant PHIs.
Fix GC steps threshold handling when called by JIT-compiled code.

Thanks to Cheng, Long.
Fix for last commit
Fix type punning alias analysis for constified pointers.
FFI: Clarify ffi.cdef behavior.
Improve msvcbuild.bat static linking.
Follow-up fix for GC step threshold fix.
Respect jit.off(func) when returning to a function, too.
x64: Fix store to upvalue for lightuserdata values.
Fix call unroll checks in the presence of metamethod frames.
Fix MinGW build.
Fix compilation of string.byte(s, nil, n).
MIPS: Cosmetic fix for interpreter.
Fix MinGW build.
Fix ABC elimination.
Bump copyright date to 2014.
FFI: Fix cts->L for cdata unsinking in snapshot restore.
Fix OSX build issue.
Fix compiler warnings.