* lisp/calendar/calendar.el (diary-file): Use locate-user-emacs-file.

* doc/emacs/calendar.texi (Diary, Format of Diary File):
Update for above diary-file change.

: * etc/NEWS: Mention this.

doc/emacs/calendar.texi

@@ -925,8 +925,9 @@ events for today, for the immediate future, or for any specified
 date.
 
   The name of the diary file is specified by the variable
-@code{diary-file}; @file{~/diary} is the default.  Here's an example
-showing what that file looks like:
+@code{diary-file}.  The default is @file{~/.emacs.d/diary}, though for
+compatibility with older versions Emacs will use @file{~/diary} if it
+exists.  Here's an example showing what the file looks like:
 
 @example
 12/22/2012  Twentieth wedding anniversary!!
@@ -1068,11 +1069,10 @@ diary-mail-entries}.  A prefix argument specifies how many days
 @vindex diary-file
   Your @dfn{diary file} is a file that records events associated with
 particular dates.  The name of the diary file is specified by the
-variable @code{diary-file}; @file{~/diary} is the default.  The
-@code{calendar} utility program supports a subset of the format allowed
-by the Emacs diary facilities, so you can use that utility to view the
-diary file, with reasonable results aside from the entries it cannot
-understand.
+variable @code{diary-file}.  The @code{calendar} utility program
+supports a subset of the format allowed by the Emacs diary facilities,
+so you can use that utility to view the diary file, with reasonable
+results aside from the entries it cannot understand.
 
   Each entry in the diary file describes one event and consists of one
 or more lines.  An entry always begins with a date specification at the

etc/NEWS

@@ -503,6 +503,9 @@ hash-table and arrays.  All functions are prefixed with "map-".
 
 ** Calendar and diary
 
++++
+*** The default `diary-file' is now located in .emacs.d.
+
 +++
 *** New commands to insert diary entries with Chinese dates:
 `diary-chinese-insert-anniversary-entry' `diary-chinese-insert-entry'

lisp/calendar/calendar.el

@@ -566,7 +566,7 @@ See also `calendar-intermonth-header'."
                         'font-lock-face 'font-lock-function-name-face)))
   :version "23.1")
 
-(defcustom diary-file "~/diary"
+(defcustom diary-file (locate-user-emacs-file "diary" "diary")
   "Name of the file in which one's personal diary of dates is kept.
 
 The file's entries are lines beginning with any of the forms
@@ -653,6 +653,7 @@ documentation of these hooks for details.
 
 Diary files can contain directives to include the contents of other files; for
 details, see the documentation for the variable `diary-list-entries-hook'."
+  :version "25.1"                  ; ~/diary -> locate-user-emacs-file
   :type 'file
   :group 'diary)