Merge remote-tracking branch 'origin/master' into staging

* origin/master:
  tcg/i386: fix build with -march < i686
  tcg: Streamline movcond_i64 using movcond_i32
  tcg: Streamline movcond_i64 using 32-bit arithmetic
  tcg: Sanity check goto_tb input
  tcg: Sanity check deposit inputs
  tcg: Add tcg_debug_assert
  tcg: Implement concat*_i64 with deposit_i64
  tcg: Emit XORI as NOT for appropriate constants
  tcg: Optimize initial inputs for ori_i64
  tcg: Emit ANDI as EXTU for appropriate constants
  tcg: Adjust descriptions of *cond opcodes
  tcg/mips: fix MIPS32(R2) detection