GlueGen: Add support for compound-array in structs (accessors) ; Allow using C-Enum values for array length

- Parser (HeaderParser.g): Support using C-Enum values for array length specification
  - Will throw an exception if enum identifier is unknown or exceeds int-size

- Add StructEmitter supports for compound-arrays

- Add Debug stderr verbose info:
  - Struct Emitter prefix 'SE.' - to analyze emitting struct fields (offset+size and accessors)
  - Struct Layout  prefix 'SL.' - to analyze memory layout (based on MachineDescription.StaticConfig.X86_64_UNIX)

Tested via test1.[ch] BaseClass ..