[rfa] `struct _bfd' -> `struct bfd'

[Andrew Cagney]

To follow this up, I've a stylistic question.  Which of:

	sec_ptr
	asection *
	struct sec *

is prefered.  GDB uses all three which makes things really confusing. 
While GDB's coding standards prefer `struct sec *' (and detest sec_ptr) 
does BFD have a stylistic preference.

Andrew