Squashed 'luajit/' changes from 80efb07..6d0654d

6d0654d Fix fused constant loads under high register pressure.
4846a71 Fix DragonFly build (unsupported).
cb886b5 DynASM/x86: Add fldenv, f[n]stenv, fxsave, fxrstor opcodes.
ae7d4d5 DynASM/x86: Add shld/shrd opcodes.
41156fe FFI: Fix initialization of unions of subtypes.
247ead6 FFI: Fix for cdata vs. non-cdata arithmetic and comparisons.
66515a0 FFI: Fix __index/__newindex metamethod resolution for ctypes.
59d2906 Invalidate backpropagation cache after DCE.
f948fe0 FFI: Fix compilation of reference field access.
a6c34b8 Fix ABC elimination.
bb5dfbb Typo.
5e7b9bb FFI: Fix frame traversal for backtraces with FFI callbacks.
7dc9e5a x86: lj_math_random_step() clobbers XMM regs on OSX Clang.
e7c6a1a Fix debug info for main chunk of stripped bytecode.
7fb503d Fix compatibility issues with Illumos.
49d3157 PPC: Fix red zone overflow in machine code generation.
fc76d54 x86: Fix code generation for unused result of math.random().
e157651 Fix FOLD rule for string.sub(s, ...) == k.
fe288e7 FFI: Fix recording of indexing a struct pointer ctype object itself.
8a38af2 Fix FOLD rule for STRREF of SNEW.
624260f Fix frame traversal while searching for error function.
2917288 x64: Workaround for MSVC build issue.
ef82bb0 FFI: Another fix for cdata equality comparisons.
7a39be0 Add PS Vita port.
2715fe3 Prevent GC estimate miscalculation due to buffer growth.
18309b0 Prevent adding side traces for stack checks.
f3374b5 x64: Allow building with LUAJIT_USE_SYSMALLOC and LUAJIT_USE_VALGRIND.
65626ea PPC: Don't use mcrxr on PPE.
cc5075e FFI: Fix cdata equality comparison against other Lua types.
4ed3ee1 FFI: Fix cdata equality comparison against strings.
111b2e8 Fix top slot calculation for snapshots with continuations.
b293063 Correct fix for reuse of SCEV results in FORL.
19b69f2 FFI: Allow non-scalar cdata to be compared for equality by address.
c735293 FFI: Fix pseudo type conversions for type punning.
095344c Fix check for reuse of SCEV results in FORL.
c03be12 x86/x64: Avoid use of SAHF instruction.
1ca794e Fix compiler warnings.
880ca30 RELEASE LuaJIT-2.0.3
30c5757 Update changelog.

git-subtree-dir: luajit
git-subtree-split: 6d0654d3eca7654c9c4f8a9923907d06b177a8a1
Merge commit 'b393759a80d17853a26f6cd4eb451709745badd9'