This removes ALL_COMPUNIT_FILETABS, replacing its uses with ranged for
loops.

Because this is still used in the ALL_OBJFILE_FILETABS macro, in some
places a declaration had to be removed or renamed to avoid shadowing.

gdb/ChangeLog
2019-01-09  Tom Tromey  <tom@tromey.com>

	* symtab.h (ALL_COMPUNIT_FILETABS): Remove.
	(compunit_filetabs): New.
	* symtab.c (iterate_over_some_symtabs, find_pc_sect_line): Use
	compunit_filetabs.
	(info_sources_command, make_source_files_completion_list): Remove
	declaration.
	* symmisc.c (print_objfile_statistics, dump_objfile)
	(maintenance_print_symbols): Remove declaration.
	(maintenance_info_symtabs): Use compunit_filetabs.
	(maintenance_info_line_tables): Likewise.
	* source.c (select_source_symtab): Change local variable name.
	(forget_cached_source_info_for_objfile): Remove declaration.
	* objfiles.h (ALL_OBJFILE_FILETABS): Use compunit_filetabs.
	* objfiles.c (objfile_relocate1): Remove declaration.
	* mi/mi-cmd-file.c (mi_cmd_file_list_exec_source_files): Remove
	declaration.
	* maint.c (count_symtabs_and_blocks): Use compunit_filetabs.
	* coffread.c (coff_symtab_read): Remove declaration.
	* buildsym.c (buildsym_compunit::end_symtab_with_blockvector): Use
	compunit_filetabs.