There's no need to forward-declare struct die_info in dwarf2read.h.
gdb/ChangeLog
2020-02-08  Tom Tromey  <tom@tromey.com>
	* dwarf2read.h (struct die_info): Don't declare.
Change-Id: I0b8dbf99558b9547d418cfd8ef387a21f7dfa660
+2020-02-08  Tom Tromey  <tom@tromey.com>
+
+       * dwarf2read.h (struct die_info): Don't declare.
+
 2020-02-08  Tom Tromey  <tom@tromey.com>
 
        * dwarf2read.h (die_info_ptr): Remove typedef.
 
 struct mapped_index;
 struct mapped_debug_names;
 struct signatured_type;
-struct die_info;
 
 /* Collection of data recorded per objfile.
    This hangs off of dwarf2_objfile_data_key.  */