fn: gcc.Function('foo')
  type(decl): <type 'gcc.TypeDecl'>
  type(decl.type): <type 'gcc.RecordType'>
  decl.type.name: gcc.IdentifierNode(name='test_struct')
    type(f): <type 'gcc.FieldDecl'>
      f.name: 'a'
      f.type: int
      type(f.type): <type 'gcc.IntegerType'>
    type(f): <type 'gcc.FieldDecl'>
      f.name: 'b'
      f.type: char
      type(f.type): <type 'gcc.IntegerType'>
    type(f): <type 'gcc.FieldDecl'>
      f.name: 'c'
      f.type: float
      type(f.type): <type 'gcc.RealType'>
