Auto merge of #218 - Amanieu:blx_fix, r=alexcrichton
Auto merge of #218 - Amanieu:blx_fix, r=alexcrichton

Fix __kuser_cmpxchg inline asm

The wrong register was passed to BLX. However I just changed them to normal function calls to simplify things.

japaric/rustc-builtins,japaric/rustc-builtins