Code is supposed to use the filename module now.
* admin/merge-gnulib (GNULIB_MODULES): Replace dosname with filename.
* lib/dosname.h: Remove this forwarding stub.
* lib/gnulib.mk.in, m4/gnulib-comp.m4: Regenerate.
* lib-src/emacsclient.c, src/fileio.c:
Include filename.h instead of dosname.h.

Original problem report by N. Jackson in:
https://lists.gnu.org/r/emacs-devel/2020-03/msg00047.html
I found some other warnings when I used gcc, and fixed them
with this patch.
* lib-src/etags.c: Include verify.h.
(xnmalloc, xnrealloc): Tell the compiler that NITEMS is
nononnegative and ITEM_SIZE is positive.
* src/conf_post.h (__has_attribute_returns_nonnull)
(ATTRIBUTE_RETURNS_NONNULL): New macros.
* src/editfns.c (Fuser_full_name): Don’t assume Fuser_login_name
returns non-nil.
* src/intervals.c (rotate_right, rotate_left, update_interval):
* src/intervals.h (LENGTH, LEFT_TOTAL_LENGTH, RIGHT_TOTAL_LENGTH):
Use TOTAL_LENGTH0 or equivalent on intervals that might be null.
* src/intervals.h (TOTAL_LENGTH): Assume arg is nonnull.
(TOTAL_LENGTH0): New macro, with the old TOTAL_LENGTH meaning.
(make_interval, split_interval_right): Add ATTRIBUTE_RETURNS_NONNULL.
* src/pdumper.c (dump_check_dump_off): Now returns void, since
no caller uses the return value.  Redo assert to pacify GCC.
(decode_emacs_reloc): Add a seemingly-random eassume to pacify GCC.
Ugly, and I suspect due to a bug in GCC.

* doc/emacs/custom.texi (Find Init): Update description of how Emacs
finds its init file directory and the interaction with
$XDG_CONFIG_HOME
(Early Init File): Correct XDG location of early-init.el

* etc/NEWS: Update description to make it clear the ~/.emacs.d is
preferred, even if the XDG location exists.

* lisp/startup.el: Prefer ~/.emacs.d even if the XDG location exists.

* lib-src/emacsclient.c (open_config): Prefer home directory the XDG
location.

These are dates that admin/update-copyright did not update.

Run "TZ=UTC0 admin/update-copyright $(git ls-files)".

* lib-src/ebrowse.c (info_where, info_cls, info_member)
(info_position, options, yyival, yytext, yytext_end, yyout)
(yyline, filename, is_ident, is_digit, is_white, f_append)
(f_verbose, f_very_verbose, f_structs, f_regexps)
(f_nested_classes, min_regexp, max_regexp, inbuffer, in)
(inbuffer_size, string_start, class_table, member_table)
(namespace_alias_table, global_symbols, current_namespace)
(all_namespaces, namespace_stack, namespace_stack_size)
(namespace_sp, tk, keyword_table, search_path)
(search_path_tail, scope_buffer, scope_buffer_size)
(scope_buffer_len): Now static.
(options): Now const.

etags had undefined behavior if input files, lines, tags, etc.,
had more than INT_MAX bytes.  Clean up the usage of integer types
to fix the overflow errors I found.
* admin/merge-gnulib (GNULIB_MODULES): Add mempcpy.
* lib-src/etags.c: Include inttypes.h, intprops.h.
(memcpyz): New function.  Use it to simplify several occurrences
of memcpy followed by storing a trailing '\0'.
(xnew): Use xnmalloc, to catch overflow on integer multiplication.
(xrnew): Change last arg to multiplier.  The type is not needed.
All callers changed.
(node, lineno, charno, linecharno, invalidcharno, make_tag):
(pfnote, add_node, number_len, C_symtype, lbz, Makefile_targets)
(readline):
Use intmax_t for line numbers and character positions, instead of
int or long.
(linebuffer, make_tag, pfnote, total_size_of_entries, put_entry)
(in_word_set, C_symtype, token, cstack, pushclass_above):
(popclass_above, write_classname, consider_token, C_entries)
(Ruby_functions, Makefile_targets, Lua_functions, TeX_commands)
(TeX_decode_env, erlang_func, erlang_attribute, erlang_atom)
(substitute, regex_tag_multiline, nocase_tail, readline_interval)
(readline, savenstr, concat, etags_getcwd, relative_filename)
(linebuffer_setlen):
Use ptrdiff_t for object sizes, instead of int or long or unsigned
or size_t.
(write_classname, C_entries):
Avoid sprintf, as the result could exceed INT_MAX bytes
and then behavior goes haywire.
(main): Use int, instead of unsigned, for argv counts.
(get_language_from_filename): Use bool for boolean.
(Ruby_functions): Prefer strcpy to memcpy when copying "=".
(linebuffer_setlen): Use ‘if’ instead of ‘while’.
(memory_full, xnmalloc, xnrealloc): New functions.
(xmalloc): Use memory_full, and take a ptrdiff_t instead of a size_t.
(xrealloc): Remove; no longer needed.
* lib/gnulib.mk.in, m4/gnulib-comp.m4: Regenerate.
* lib/mempcpy.c, m4/mempcpy.m4: New files, copied from Gnulib.