Give these bfd-internal symbols with external linkage a _bfd_ prefix
to avoid collisions in the global symbol namespace.

bfd/ChangeLog:
2017-02-17  Pedro Alves  <palves@redhat.com>

	* archive.c (bsd_write_armap): Rename to ...
	(_bfd_bsd_write_armap): ... this.
	(coff_write_armap): Rename to ...
	(_bfd_coff_write_armap): ... this.
	* libbfd-in.h (bsd_write_armap): Rename to ...
	(_bfd_bsd_write_armap): ... this.
	(coff_write_armap): Rename to ...
	(_bfd_coff_write_armap): ... this.
	* aout-target.h, aout-tic30.c: Adjust all users.
	* libbfd.h: Regenerate.