Adds "#ifndef NOT_DYNAMORIO_CORE_PROPER" around the two option references in module_elf.c in order to remove the problematic drdecode dependence from drfrontendlib. (The drhelper library added in the past already removed the dynamorio_syscall dependence for us.)
Adds disabling of inlining from instr.h and opnd.h for drhelper who just wants to include globals.h, to avoid pulling in extra deps.
Issue: #1409