vxworks.h (DBX_REGISTER_NUMBER): Pick distinct map for 64bits.

vxworks.h (DBX_REGISTER_NUMBER): Pick distinct map for 64bits.

2017-06-27  Jerome Lambourg  <lambourg@adacore.com>
            Olivier Hainque  <hainque@adacore.com>

	* config/i386/vxworks.h (DBX_REGISTER_NUMBER): Pick distinct
	map for 64bits.
	(TARGET_OS_CPP_BUILTINS): builtin_define CPU to X86_64 for 64bit
	targets. Pick a default if no particular attempt applied.
	(STACK_CHECK_PROTECT): Double for 64bit targets, which have
	larger contexts.

Co-Authored-By: Olivier Hainque <hainque@adacore.com>
From-SVN: r249690