x86: Fix code generation for unused result of math.random().
PPC: Fix red zone overflow in machine code generation.
Merge branch 'master' into v2.1
Fix compatibility issues with Illumos.

Thanks to Theo Schlossnagle.
Merge branch 'master' into v2.1
Fix debug info for main chunk of stripped bytecode.
Merge branch 'master' into v2.1
x86: lj_math_random_step() clobbers XMM regs on OSX Clang.
Merge branch 'master' into v2.1
FFI: Fix frame traversal for backtraces with FFI callbacks.
Merge branch 'master' into v2.1
Typo.
Merge branch 'master' into v2.1
Compile debug.getmetatable().

Thanks to Karel Tuma.
Fix ABC elimination.
Merge branch 'master' into v2.1
FFI: Fix compilation of reference field access.
Merge branch 'master' into v2.1
Invalidate backpropagation cache after DCE.
Merge branch 'master' into v2.1