i#1551 port to ARM: fix drdecodelib build
i#1551 port to ARM: fix drdecodelib build

Add NOT_DYNAMORIO_CORE_PROPER around master_signal_handler to fix drdecode
build broken by 51dc400193d84903f77818db7ff422cf9bfd9403.

Review-URL: https://codereview.appspot.com/198650043

code4bones/dynamorio,sigma-random/dynamorio,daksunt/dynamorio,AmesianX/dynamorio,bl4ckic3/dynamorio,bl4ckic3/dynamorio,AmesianX/dynamorio,sigma-random/dynamorio,code4bones/dynamorio,bl4ckic3/dynamorio,code4bones/dynamorio,AmesianX/dynamorio,code4bones/dynamorio,sigma-random/dynamorio,bl4ckic3/dynamorio,sigma-random/dynamorio,AmesianX/dynamorio,AmesianX/dynamorio,daksunt/dynamorio,daksunt/dynamorio,daksunt/dynamorio,bl4ckic3/dynamorio,daksunt/dynamorio,sigma-random/dynamorio,code4bones/dynamorio