This changes read_indirect_string_from_dwz to be a method on the
dwz_file, and adds a new dwarf2/dwz.c file.
gdb/ChangeLog
2020-03-26 Tom Tromey <tom@tromey.com>
* dwarf2/read.c (read_attribute_value): Update.
(read_indirect_string_from_dwz): Move to dwz.c; change into
method.
(dwarf_decode_macro_bytes): Update.
* dwarf2/dwz.h (struct dwz_file) <read_string>: Declare method.
* dwarf2/dwz.c: New file.
* Makefile.in (COMMON_SFILES): Add dwz.c.