* ldemul.h (ldemul_open_dynamic_archive): Declare.

	* ldemul.h (ldemul_open_dynamic_archive): Declare.
	(ld_emulation_xfer_type): Add new field open_dynamic_archive.
	* ldemul.c: Include ldexp.h and ldlang.h.
	(ldemul_open_dynamic_archive): New function.
	* ldfile.h (ldfile_open_file_search): Declare.
	* ldfile.c: Include ldemul.h.
	(try_open_bfd): Rename from cache_bfd_openr.  Return boolean
	argument, not bfd *.  Change all callers.
	(ldfile_open_file_search): Rename from open_a.  Return boolean
	argument, not bfd *.  Clean up.  Change all callers.
	(ldfile_open_file): If doing a dynamic link, call
	ldemul_open_dynamic_archive rather than assuming the extension of
	a dynamic object is ".so".
	* emultempl/elf32.em (gld${EMULATION_NAME}_open_dynamic_archive):
	New function.
	(ld_${EMULATION_NAME}_emulation): Initialize open_dynamic_archive
	field.
	* emultempl/sunos.em (ld_${EMULATION_NAME}_emulation): Likewise.