* coffread.c, mipsread.c, xcoffread.c, coffread.c, dbxread.c,

	* coffread.c, mipsread.c, xcoffread.c, coffread.c, dbxread.c,
	elfread.c (coff_symfile_finish):  Add function, prototype, and
	add to the xxxx_sym_fns struct for each file type.  Also reformat
	the xxxx_sym_fns vector to a standard format and add comments.
	* coffread.c, mipsread.c, xcoffread.c, coffread.c, dbxread.c,
	elfread.c (xxx_symfile_new_init, xxx_symfile_init, xxx_symfile_read):
	Pass pointer to struct objfile rather than pointer to sym_fns.
	Change references inside each function accordingly.  Allocate any
	symbol file specific info in the per-objfile memory region.
	* dbxread.c (free_and_init_header_files):  Break function into
	free_header_files(), called from dbx_symfile_finish(), and
	init_header_files(), called from dbx_new_init().
	* dbxread.c (dbx_new_init):  Move deallocation things to new
	dbx_symfile_finish function.
	* elfread.c (elf_new_init):  Call buildsym_new_init().
	* objfiles.c (free_objfile): Call the appropriate symfile_finish()
	routine for the objfile before deallocating other stuff.
	* sparc-tdep.c (get_longjmp_target):  Cast target_read_memory arg.
	* symfile.h:  Move struct sym_fns to before struct objfile def.
	Add sym_finish function pointer and change prototypes of other
	function pointers to reflect passing struct objfile pointer rather
	than struct sym_fns pointer.
	* symfile.c:  Remove now obsolete symtab_fns pointer.
	* symfile.c (symfile_init):  Renamed to find_sym_fns, and now only
	locates the correct sym_fns struct for the given objfile.
	* symfile.c (syms_from_objfile, symbol_file_add):  Restructured
	for better support of mapped symbol tables.
	* symfile.c (symbol_file_command):  Remove obsolete code using
	symfile_fns.
	* symfile.h:  Remove duplicate declarations for symfile_objfile,
	entry_point, and object_files.
	* target.c (target_info):  Compare symfile_objfile to NULL.
	* xcoffread.c (aixcoff_new_init):  Move deallocation stuff to
	aixcoff_symfile_finish().