update luajit-2.0

* submodules/luajit-2.0 474bb21...a31c317 (76):
  > FFI: No meta fallback when indexing pointer to incomplete struct.
  > Fix fused constant loads under high register pressure.
  > Fix DragonFly build (unsupported).
  > DynASM/x86: Add fldenv, f[n]stenv, fxsave, fxrstor opcodes.
  > DynASM/x86: Add shld/shrd opcodes.
  > FFI: Fix initialization of unions of subtypes.
  > FFI: Fix for cdata vs. non-cdata arithmetic and comparisons.
  > FFI: Fix __index/__newindex metamethod resolution for ctypes.
  > Invalidate backpropagation cache after DCE.
  > FFI: Fix compilation of reference field access.
  > Fix ABC elimination.
  > Typo.
  > FFI: Fix frame traversal for backtraces with FFI callbacks.
  > x86: lj_math_random_step() clobbers XMM regs on OSX Clang.
  > Fix debug info for main chunk of stripped bytecode.
  > Fix compatibility issues with Illumos.
  > PPC: Fix red zone overflow in machine code generation.
  > x86: Fix code generation for unused result of math.random().
  > Fix FOLD rule for string.sub(s, ...) == k.
  > FFI: Fix recording of indexing a struct pointer ctype object itself.
  > Fix FOLD rule for STRREF of SNEW.
  > Fix frame traversal while searching for error function.
  > x64: Workaround for MSVC build issue.
  > FFI: Another fix for cdata equality comparisons.
  > Add PS Vita port.
  > Prevent GC estimate miscalculation due to buffer growth.
  > Prevent adding side traces for stack checks.
  > x64: Allow building with LUAJIT_USE_SYSMALLOC and LUAJIT_USE_VALGRIND.
  > PPC: Don't use mcrxr on PPE.
  > FFI: Fix cdata equality comparison against other Lua types.
  > FFI: Fix cdata equality comparison against strings.
  > Fix top slot calculation for snapshots with continuations.
  > Correct fix for reuse of SCEV results in FORL.
  > FFI: Allow non-scalar cdata to be compared for equality by address.
  > FFI: Fix pseudo type conversions for type punning.
  > Fix check for reuse of SCEV results in FORL.
  > x86/x64: Avoid use of SAHF instruction.
  > Fix compiler warnings.
  > RELEASE LuaJIT-2.0.3
  > Update changelog.
  > DynASM: Emit version check after .arch directive.
  > Don't access dangling reference to reallocated IR.
  > Fix frame depth display for bytecode dump in -jdump.
  > Fix recording of BC_VARG.
  > Fix for -jdump docs.
  > Add PS4 port.
  > Don't purge modified function from stack slots in BC_RET.
  > FFI: Disallow nested VLS.
  > Prevent BASE register coalescing if parent uses IR_RETF.
  > Fix quoting in xedkbuild.bat (again).
  > Fix exception unwind struct declaration.
  > Fix OSX build issue.
  > Fix initial maxslot for down-recursive traces.
  > Fix compiler warnings.
  > Fix OSX build issue.
  > FFI: Fix cts->L for cdata unsinking in snapshot restore.
  > Bump copyright date to 2014.
  > Fix ABC elimination.
  > Fix MinGW build.
  > MIPS: Cosmetic fix for interpreter.
  > Fix compilation of string.byte(s, nil, n).
  > Fix MinGW build.
  > Fix call unroll checks in the presence of metamethod frames.
  > x64: Fix store to upvalue for lightuserdata values.
  > Respect jit.off(func) when returning to a function, too.
  > Follow-up fix for GC step threshold fix.
  > Improve msvcbuild.bat static linking.
  > FFI: Clarify ffi.cdef behavior.
  > Fix type punning alias analysis for constified pointers.
  > Fix for last commit
  > Fix GC steps threshold handling when called by JIT-compiled code.
  > Fix handling of redundant PHIs.
  > Check for failure to mark memory as executable (restricted kernels).
  > Fix line number for relocated bytecode after closure fixup.
  > FFI: Rehash finalizer table after GC cycle, if needed.
  > Check for MAP_32BIT presence instead of checking for Linux.
Merge into master from pull request #213:
update submodules (https://github.com/floodlight/ivs/pull/213)