ee9b84f5be
This patch defines the structures and constants used by the SFrame unwind info format supported by GNU binutils. For more information about the format, see https://sourceware.org/binutils/wiki/sframe and https://discourse.llvm.org/t/rfc-adding-sframe-support-to-llvm/86900 The patch uses the GNU names for all relevant entities, but I've converted them to the llvm naming convention, and I've replaced macros with enums.