GitLab

	* frags.h (bss_address_frag): Delete
	(predefined_address_frag): New.
	* frags.c (frag_init): Init predefined_address_frag.  Delete ref
	to bss_addres_frag.
	* symbols.c (S_CAN_BE_REDEFINED): New function.
	* symbols.h (S_CAN_BE_REDEFINED): Declare.
	* read.c (assign_symbol): Use S_CAN_BE_REDEFINED.