Separates the public parts of core/ir/opnd.h (which is most of the file) to a new file core/ir/opnd_api.h, which is exported to dr_ir_opnd.h. Uses DYNAMORIO_INTERNAL to set inlining and other flags properly for core vs client use.
Moves the OPSZ_ enum from decode.h to opnd_api.h.
Separates the public parts of core/ir/instrlist.h to a new file core/ir/instrlist_api.h, which is exported to dr_ir_instrlist.h.
Updates dcontext_t* to void* for exported functions.
Issue: #3092 (closed)