i#1551 port to ARM: add ARM_32 and ARM_64 for clients

Clients now have to set one of X86_32, X86_64, ARM_32, or ARM_64 (or use
find_package which will do that for them).
Our headers, from those, then auto-set X86, ARM, X64.

git-svn-id: https://dynamorio.googlecode.com/svn/trunk@3013 49cc7528-f6fd-11dd-9d1a-b59b2e1864b6
3 files changed