24 files changed, 76 insertions, 77 deletions

diff --git a/src/coding.c b/src/coding.c
index b82d4f5cda9..feed9c8274c 100644
--- a/src/coding.c
+++ b/src/coding.c
@@ -122,7 +122,7 @@ END-OF-LINE FORMAT
   How text end-of-line is encoded depends on operating system.  For
   instance, Unix's format is just one byte of LF (line-feed) code,
   whereas DOS's format is two-byte sequence of `carriage-return' and
-  `line-feed' codes.  MacOS's format is usually one byte of
+  `line-feed' codes.  Classic Mac OS's format is usually one byte of
   `carriage-return'.
 
   Since text character encoding and end-of-line encoding are
diff --git a/src/conf_post.h b/src/conf_post.h
index 9c544e89e94..060b912fafb 100644
--- a/src/conf_post.h
+++ b/src/conf_post.h
@@ -186,7 +186,7 @@ You lose; /* Emacs for DOS must be compiled with DJGPP */
 #endif
 #endif  /* MSDOS */
 
-/* Mac OS X / GNUstep need a bit more pure memory.  Of the existing knobs,
+/* macOS / GNUstep need a bit more pure memory.  Of the existing knobs,
    SYSTEM_PURESIZE_EXTRA seems like the least likely to cause problems.  */
 #ifdef HAVE_NS
 #if defined NS_IMPL_GNUSTEP
diff --git a/src/emacs-module.c b/src/emacs-module.c
index 5075263edff..68aeb0ce704 100644
--- a/src/emacs-module.c
+++ b/src/emacs-module.c
@@ -147,8 +147,8 @@ static emacs_value const module_nil = 0;
    or a pointer to handle non-local exits.  The function must have an
    ENV parameter.  The function will return the specified value if a
    signal or throw is caught.  */
-// TODO: Have Fsignal check for CATCHER_ALL so we only have to install
-// one handler.
+/* TODO: Have Fsignal check for CATCHER_ALL so we only have to install
+   one handler.  */
 #define MODULE_HANDLE_NONLOCAL_EXIT(retval)                     \
   MODULE_SETJMP (CONDITION_CASE, module_handle_signal, retval); \
   MODULE_SETJMP (CATCHER_ALL, module_handle_throw, retval)
@@ -168,7 +168,7 @@ static emacs_value const module_nil = 0;
    code after the macro may longjmp back into the macro, which means
    its local variable C must stay live in later code.  */
 
-// TODO: Make backtraces work if this macros is used.
+/* TODO: Make backtraces work if this macros is used.  */
 
 #define MODULE_SETJMP_1(handlertype, handlerfunc, retval, c, dummy)     \
   if (module_non_local_exit_check (env) != emacs_funcall_exit_return)   \
diff --git a/src/emacs.c b/src/emacs.c
index d86c34fd1fd..efd4fa329df 100644
--- a/src/emacs.c
+++ b/src/emacs.c
@@ -2504,7 +2504,7 @@ Special values:
   `gnu'          compiled for a GNU Hurd system.
   `gnu/linux'    compiled for a GNU/Linux system.
   `gnu/kfreebsd' compiled for a GNU system with a FreeBSD kernel.
-  `darwin'       compiled for Darwin (GNU-Darwin, Mac OS X, ...).
+  `darwin'       compiled for Darwin (GNU-Darwin, macOS, ...).
   `ms-dos'       compiled as an MS-DOS application.
   `windows-nt'   compiled as a native W32 application.
   `cygwin'       compiled using the Cygwin library.
diff --git a/src/frame.c b/src/frame.c
index 3a2d009d325..b1d89f396ec 100644
--- a/src/frame.c
+++ b/src/frame.c
@@ -5110,7 +5110,7 @@ Setting this variable does not affect existing frames, only new ones.  */);
                doc: /* Default position of vertical scroll bars on this window-system.  */);
 #ifdef HAVE_WINDOW_SYSTEM
 #if defined (HAVE_NTGUI) || defined (NS_IMPL_COCOA) || (defined (USE_GTK) && defined (USE_TOOLKIT_SCROLL_BARS))
-  /* MS-Windows, Mac OS X, and GTK have scroll bars on the right by
+  /* MS-Windows, macOS, and GTK have scroll bars on the right by
      default.  */
   Vdefault_frame_scroll_bars = Qright;
 #else
diff --git a/src/gfilenotify.c b/src/gfilenotify.c
index 3b1f2fc516a..30d0753f7e7 100644
--- a/src/gfilenotify.c
+++ b/src/gfilenotify.c
@@ -105,7 +105,7 @@ dir_monitor_callback (GFileMonitor *monitor,
 
           /* Store it into the input event queue.  */
           kbd_buffer_store_event (&event);
-          // XD_DEBUG_MESSAGE ("%s", XD_OBJECT_TO_STRING (event.arg));
+          /* XD_DEBUG_MESSAGE ("%s", XD_OBJECT_TO_STRING (event.arg));  */
         }
 
       /* Cancel monitor if file or directory is deleted.  */
diff --git a/src/gtkutil.c b/src/gtkutil.c
index 986eca85587..3d35a3dee81 100644
--- a/src/gtkutil.c
+++ b/src/gtkutil.c
@@ -191,7 +191,7 @@ xg_display_open (char *display_name, Display **dpy)
 {
   GdkDisplay *gdpy;
 
-  unrequest_sigio ();  // See comment in x_display_ok, xterm.c.
+  unrequest_sigio ();  /* See comment in x_display_ok, xterm.c.  */
   gdpy = gdk_display_open (display_name);
   request_sigio ();
   if (!gdpy_def && gdpy)
@@ -2386,7 +2386,7 @@ make_widget_for_menu_item (const char *utf8_label, const char *utf8_key)
    in the group.  On exit, *GROUP contains the radio item group.
 
    Unfortunately, keys don't line up as nicely as in Motif,
-   but the MacOS X version doesn't either, so I guess that is OK.  */
+   but the macOS version doesn't either, so I guess that is OK.  */
 
 static GtkWidget *
 make_menu_item (const char *utf8_label,
diff --git a/src/image.c b/src/image.c
index 1303a931263..d82fedb8dea 100644
--- a/src/image.c
+++ b/src/image.c
@@ -3718,7 +3718,7 @@ xpm_load (struct frame *f, struct image *img)
     }
 
 #ifdef USE_CAIRO
-  // Load very specific Xpm:s.
+  /* Load very specific Xpm:s.  */
   if (rc == XpmSuccess
       && img->ximg->format == ZPixmap
       && img->ximg->bits_per_pixel == 32
@@ -3742,7 +3742,7 @@ xpm_load (struct frame *f, struct image *img)
               int maskidx = mid ? i * img->mask_img->bytes_per_line + k/8 : 0;
               int mask = mid ? mid[maskidx] & (1 << (k % 8)) : 1;
 
-              if (mask) od[idx] = id[idx] + 0xff000000; // ff => full alpha
+              if (mask) od[idx] = id[idx] + 0xff000000; /* ff => full alpha */
               else od[idx] = bgcolor;
             }
         }
diff --git a/src/kqueue.c b/src/kqueue.c
index f45bd0c4c24..d1d0a612044 100644
--- a/src/kqueue.c
+++ b/src/kqueue.c
@@ -268,8 +268,6 @@ kqueue_compare_dir_list (Lisp_Object watch_object)
     report_file_error ("New list not empty", new_dl);
   if (! NILP (pending_dl))
     report_file_error ("Pending events list not empty", pending_dl);
-  //  if (! NILP (deleted_dl))
-  //    report_file_error ("Deleted events list not empty", deleted_dl);
 
   /* Replace old directory listing with the new one.  */
   XSETCDR (Fnthcdr (make_number (3), watch_object),
diff --git a/src/macfont.h b/src/macfont.h
index 6630fb526b7..8f734527a46 100644
--- a/src/macfont.h
+++ b/src/macfont.h
@@ -1,4 +1,4 @@
-/* Interface definition for Mac OSX Core text font backend.
+/* Interface definition for macOS Core text font backend.
    Copyright (C) 2009-2016 Free Software Foundation, Inc.
 
 This file is part of GNU Emacs.
diff --git a/src/macfont.m b/src/macfont.m
index d9bad034fe9..3af9edc148a 100644
--- a/src/macfont.m
+++ b/src/macfont.m
@@ -1,4 +1,4 @@
-/* Font driver on Mac OSX Core text.
+/* Font driver on macOS Core text.
    Copyright (C) 2009-2016 Free Software Foundation, Inc.
 
 This file is part of GNU Emacs.
@@ -1005,7 +1005,7 @@ macfont_set_family_cache (Lisp_Object symbol, CFStringRef string)
 and those start with ".".  NULL means the cache has been invalidated.
 Otherwise, the value is CFArray of CFStrings and the elements are
 sorted in the canonical order (CTFontManagerCompareFontFamilyNames on
-OS X 10.6 and later).  */
+Mac OS X 10.6 and later).  */
 
 static CFArrayRef macfont_available_families_cache = NULL;
 
@@ -4057,7 +4057,7 @@ mac_register_font_driver (struct frame *f)
 void
 syms_of_macfont (void)
 {
-  /* Core Text, for Mac OS X.  */
+  /* Core Text, for macOS.  */
   DEFSYM (Qmac_ct, "mac-ct");
   macfont_driver.type = Qmac_ct;
   register_font_driver (&macfont_driver, NULL);
diff --git a/src/nsfns.m b/src/nsfns.m
index b8264608b34..cfaaf53cbc6 100644
--- a/src/nsfns.m
+++ b/src/nsfns.m
@@ -1,4 +1,4 @@
-/* Functions for the NeXT/Open/GNUstep and MacOSX window system.
+/* Functions for the NeXT/Open/GNUstep and macOS window system.
 
 Copyright (C) 1989, 1992-1994, 2005-2006, 2008-2016 Free Software
 Foundation, Inc.
@@ -22,7 +22,7 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 Originally by Carl Edman
 Updated by Christian Limpach (chris@nice.ch)
 OpenStep/Rhapsody port by Scott Bender (sbender@harmony-ds.com)
-MacOSX/Aqua port by Christophe de Dinechin (descubes@earthlink.net)
+macOS/Aqua port by Christophe de Dinechin (descubes@earthlink.net)
 GNUstep port and post-20 update by Adrian Robert (arobert@cogsci.ucsd.edu)
 */
 
@@ -905,7 +905,7 @@ static void
 x_icon (struct frame *f, Lisp_Object parms)
 /* --------------------------------------------------------------------------
    Strangely-named function to set icon position parameters in frame.
-   This is irrelevant under OS X, but might be needed under GNUstep,
+   This is irrelevant under macOS, but might be needed under GNUstep,
    depending on the window manager used.  Note, this is not a standard
    frame parameter-setter; it is called directly from x-create-frame.
    -------------------------------------------------------------------------- */
@@ -2024,7 +2024,7 @@ DEFUN ("ns-list-services", Fns_list_services, Sns_list_services, 0, 0, 0,
 
   [svcs setAutoenablesItems: NO];
 #ifdef NS_IMPL_COCOA
-  [svcs update]; /* on OS X, converts from '/' structure */
+  [svcs update]; /* on macOS, converts from '/' structure */
 #endif
 
   ret = interpret_services_menu (svcs, Qnil, ret);
diff --git a/src/nsfont.m b/src/nsfont.m
index be7d2ec36b9..389d0ed7aa4 100644
--- a/src/nsfont.m
+++ b/src/nsfont.m
@@ -1,4 +1,4 @@
-/* Font back-end driver for the NeXT/Open/GNUstep and MacOSX window system.
+/* Font back-end driver for the NeXT/Open/GNUstep and macOS window system.
    See font.h
    Copyright (C) 2006-2016 Free Software Foundation, Inc.
 
@@ -497,7 +497,7 @@ static NSSet
                   {
                     NSCharacterSet *fset = [[fontMgr fontWithFamily: family
                         traits: 0 weight: 5 size: 12.0] coveredCharacterSet];
-                    /* Some fonts on OS X, maybe many on GNUstep, return nil. */
+                    /* Some fonts on macOS, maybe many on GNUstep, return nil. */
                     if (fset == nil)
                       fset = [NSCharacterSet characterSetWithRange:
                                                NSMakeRange (0, 127)];
diff --git a/src/nsimage.m b/src/nsimage.m
index 6d1b3937f94..32bcea76ccd 100644
--- a/src/nsimage.m
+++ b/src/nsimage.m
@@ -1,4 +1,4 @@
-/* Image support for the NeXT/Open/GNUstep and MacOSX window system.
+/* Image support for the NeXT/Open/GNUstep and macOS window system.
    Copyright (C) 1989, 1992-1994, 2005-2006, 2008-2016 Free Software
    Foundation, Inc.
 
@@ -21,7 +21,7 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 Originally by Carl Edman
 Updated by Christian Limpach (chris@nice.ch)
 OpenStep/Rhapsody port by Scott Bender (sbender@harmony-ds.com)
-MacOSX/Aqua port by Christophe de Dinechin (descubes@earthlink.net)
+macOS/Aqua port by Christophe de Dinechin (descubes@earthlink.net)
 GNUstep port and post-20 update by Adrian Robert (arobert@cogsci.ucsd.edu)
 */
 
diff --git a/src/nsmenu.m b/src/nsmenu.m
index 470d6d0dbcf..3e9887acf5d 100644
--- a/src/nsmenu.m
+++ b/src/nsmenu.m
@@ -1,4 +1,4 @@
-/* NeXT/Open/GNUstep and MacOSX Cocoa menu and toolbar module.
+/* NeXT/Open/GNUstep and macOS Cocoa menu and toolbar module.
    Copyright (C) 2007-2016 Free Software Foundation, Inc.
 
 This file is part of GNU Emacs.
@@ -92,7 +92,7 @@ popup_activated (void)
 /* --------------------------------------------------------------------------
     Update menubar.  Three cases:
     1) ! deep_p, submenu = nil: Fresh switch onto a frame -- either set up
-       just top-level menu strings (OS X), or goto case (2) (GNUstep).
+       just top-level menu strings (macOS), or goto case (2) (GNUstep).
     2) deep_p, submenu = nil: Recompute all submenus.
     3) deep_p, submenu = non-nil: Update contents of a single submenu.
    -------------------------------------------------------------------------- */
@@ -577,7 +577,7 @@ x_activate_menubar (struct frame *f)
     return;
 /*fprintf (stderr, "Updating menu '%s'\n", [[self title] UTF8String]); NSLog (@"%@\n", event); */
 #ifdef NS_IMPL_GNUSTEP
-  /* Don't know how to do this for anything other than OSX >= 10.5
+  /* Don't know how to do this for anything other than Mac OS X 10.5 and later.
      This is wrong, as it might run Lisp code in the event loop.  */
   ns_update_menubar (frame, true, self);
 #endif
@@ -638,7 +638,7 @@ x_activate_menubar (struct frame *f)
 
       keyEq = [self parseKeyEquiv: wv->key];
 #ifdef NS_IMPL_COCOA
-      /* OS X just ignores modifier strings longer than one character */
+      /* macOS just ignores modifier strings longer than one character */
       if (keyEquivModMask == 0)
         title = [title stringByAppendingFormat: @" (%@)", keyEq];
 #endif
@@ -1048,9 +1048,9 @@ update_frame_tool_bar (struct frame *f)
       /* Check if this is a separator.  */
       if (EQ (TOOLPROP (TOOL_BAR_ITEM_TYPE), Qt))
         {
-          /* Skip separators.  Newer OSX don't show them, and on GNUstep they
-             are wide as a button, thus overflowing the toolbar most of
-             the time.  */
+          /* Skip separators.  Newer macOS don't show them, and on
+             GNUstep they are wide as a button, thus overflowing the
+             toolbar most of the time.  */
           continue;
         }
 
diff --git a/src/nsselect.m b/src/nsselect.m
index eba23932e65..b7c9148ee05 100644
--- a/src/nsselect.m
+++ b/src/nsselect.m
@@ -1,4 +1,4 @@
-/* NeXT/Open/GNUstep / MacOSX Cocoa selection processing for emacs.
+/* NeXT/Open/GNUstep / macOS Cocoa selection processing for emacs.
    Copyright (C) 1993-1994, 2005-2006, 2008-2016 Free Software
    Foundation, Inc.
 
@@ -21,7 +21,7 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 Originally by Carl Edman
 Updated by Christian Limpach (chris@nice.ch)
 OpenStep/Rhapsody port by Scott Bender (sbender@harmony-ds.com)
-MacOSX/Aqua port by Christophe de Dinechin (descubes@earthlink.net)
+macOS/Aqua port by Christophe de Dinechin (descubes@earthlink.net)
 GNUstep port and post-20 update by Adrian Robert (arobert@cogsci.ucsd.edu)
 */
 
diff --git a/src/nsterm.m b/src/nsterm.m
index 1b44a73cd8b..7e6ec85abf1 100644
--- a/src/nsterm.m
+++ b/src/nsterm.m
@@ -1,4 +1,4 @@
-/* NeXT/Open/GNUstep / MacOSX communication module.      -*- coding: utf-8 -*-
+/* NeXT/Open/GNUstep / macOS communication module.      -*- coding: utf-8 -*-
 
 Copyright (C) 1989, 1993-1994, 2005-2006, 2008-2016 Free Software
 Foundation, Inc.
@@ -22,7 +22,7 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 Originally by Carl Edman
 Updated by Christian Limpach (chris@nice.ch)
 OpenStep/Rhapsody port by Scott Bender (sbender@harmony-ds.com)
-MacOSX/Aqua port by Christophe de Dinechin (descubes@earthlink.net)
+macOS/Aqua port by Christophe de Dinechin (descubes@earthlink.net)
 GNUstep port and post-20 update by Adrian Robert (arobert@cogsci.ucsd.edu)
 */
 
@@ -251,7 +251,7 @@ static unsigned convert_ns_to_X_keysym[] =
   0x1B,                         0x1B   /* escape */
 };
 
-/* On OS X picks up the default NSGlobalDomain AppleAntiAliasingThreshold,
+/* On macOS picks up the default NSGlobalDomain AppleAntiAliasingThreshold,
    the maximum font size to NOT antialias.  On GNUstep there is currently
    no way to control this behavior. */
 float ns_antialias_threshold;
@@ -588,7 +588,7 @@ ns_load_path (void)
 
 void
 ns_init_locale (void)
-/* OS X doesn't set any environment variables for the locale when run
+/* macOS doesn't set any environment variables for the locale when run
    from the GUI. Get the locale from the OS and set LANG. */
 {
   NSLocale *locale = [NSLocale currentLocale];
@@ -597,7 +597,7 @@ ns_init_locale (void)
 
   @try
     {
-      /* It seems OS X should probably use UTF-8 everywhere.
+      /* It seems macOS should probably use UTF-8 everywhere.
          'localeIdentifier' does not specify the encoding, and I can't
          find any way to get the OS to tell us which encoding to use,
          so hard-code '.UTF-8'. */
@@ -719,7 +719,7 @@ ns_screen_margins (NSScreen *screen)
 
 
 /* A screen margin between 1 and DOCK_IGNORE_LIMIT (inclusive) is
-   assumed to contain a hidden dock.  OS X currently use 4 pixels for
+   assumed to contain a hidden dock.  macOS currently use 4 pixels for
    this, however, to be future compatible, a larger value is used.  */
 #define DOCK_IGNORE_LIMIT 6
 
@@ -732,7 +732,7 @@ reserved for an hidden dock.  */
 
   struct EmacsMargins margins = ns_screen_margins(screen);
 
-  /* OS X (currently) reserved 4 pixels along the edge where a hidden
+  /* macOS (currently) reserved 4 pixels along the edge where a hidden
      dock is located.  Unfortunately, it's not possible to find the
      location and information about if the dock is hidden.  Instead,
      it is assumed that if the margin of an edge is less than
@@ -749,7 +749,7 @@ reserved for an hidden dock.  */
     {
       margins.top = 0;
     }
-  /* Note: This doesn't occur in current versions of OS X, but
+  /* Note: This doesn't occur in current versions of macOS, but
      included for completeness and future compatibility.  */
   if (margins.bottom <= DOCK_IGNORE_LIMIT)
     {
@@ -1028,7 +1028,7 @@ ns_update_begin (struct frame *f)
 #ifdef NS_IMPL_COCOA
   if ([view isFullscreen] && [view fsIsNative])
   {
-    // Fix reappearing tool bar in fullscreen for OSX 10.7
+    // Fix reappearing tool bar in fullscreen for Mac OS X 10.7
     BOOL tbar_visible = FRAME_EXTERNAL_TOOL_BAR (f) ? YES : NO;
     NSToolbar *toolbar = [FRAME_NS_VIEW (f) toolbar];
     if (! tbar_visible != ! [toolbar isVisible])
@@ -1940,8 +1940,8 @@ ns_get_color (const char *name, NSColor **col)
     }
   else if ([nsname isEqualToString: @"ns_selection_fg_color"])
     {
-      /* NOTE: OSX applications normally don't set foreground selection, but
-         text may be unreadable if we don't.
+      /* NOTE: macOS applications normally don't set foreground
+         selection, but text may be unreadable if we don't.
       */
       if ((new = [NSColor selectedTextColor]) != nil)
         {
@@ -3879,7 +3879,7 @@ ns_send_appdefined (int value)
 #ifdef NS_IMPL_COCOA
   if (! send_appdefined)
     {
-      /* OSX 10.10.1 swallows the AppDefined event we are sending ourselves
+      /* OS X 10.10.1 swallows the AppDefined event we are sending ourselves
          in certain situations (rapid incoming events).
          So check if we have one, if not add one.  */
       NSEvent *appev = [NSApp nextEventMatchingMask:NSEventMaskApplicationDefined
@@ -4758,7 +4758,7 @@ ns_term_init (Lisp_Object display_name)
   [outerpool release];
   outerpool = [[NSAutoreleasePool alloc] init];
 
-  /* count object allocs (About, click icon); on OS X use ObjectAlloc tool */
+  /* count object allocs (About, click icon); on macOS use ObjectAlloc tool */
   /*GSDebugAllocationActive (YES); */
   block_input ();
 
@@ -4887,7 +4887,7 @@ ns_term_init (Lisp_Object display_name)
 
   ns_app_name = [[NSProcessInfo processInfo] processName];
 
-  /* Set up OS X app menu */
+  /* Set up macOS app menu */
 
   NSTRACE_MSG ("Menu init");
 
@@ -4959,7 +4959,7 @@ ns_term_init (Lisp_Object display_name)
          selector: @selector (trackingNotification:)
              name: NSMenuDidEndTrackingNotification object: mainMenu];
   }
-#endif /* MAC OS X menu setup */
+#endif /* macOS menu setup */
 
   /* Register our external input/output types, used for determining
      applicable services and also drag/drop eligibility. */
@@ -5187,7 +5187,7 @@ ns_term_shutdown (int sig)
 
 #ifdef NS_IMPL_COCOA
   /* If no dialog and none of our frames have focus and it is a move, skip it.
-     It is a mouse move in an auxiliary menu, i.e. on the top right on OSX,
+     It is a mouse move in an auxiliary menu, i.e. on the top right on macOS,
      such as Wifi, sound, date or similar.
      This prevents "spooky" highlighting in the frame under the menu.  */
   if (type == NSEventTypeMouseMoved && [NSApp modalWindow] == nil)
@@ -5722,7 +5722,7 @@ not_in_argv (NSString *arg)
 
   NSTRACE ("[EmacsView keyDown:]");
 
-  /* Rhapsody and OS X give up and down events for the arrow keys */
+  /* Rhapsody and macOS give up and down events for the arrow keys */
   if (ns_fake_keydown == YES)
     ns_fake_keydown = NO;
   else if ([theEvent type] != NSEventTypeKeyDown)
@@ -5956,7 +5956,7 @@ not_in_argv (NSString *arg)
 
 
 #ifdef NS_IMPL_COCOA
-/* Needed to pick up Ctrl-tab and possibly other events that OS X has
+/* Needed to pick up Ctrl-tab and possibly other events that Mac OS X
    decided not to send key-down for.
    See http://osdir.com/ml/editors.vim.mac/2007-10/msg00141.html
    This only applies on Tiger and earlier.
@@ -7121,8 +7121,8 @@ not_in_argv (NSString *arg)
 #if MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_7
       unsigned val = (unsigned)[NSApp presentationOptions];
 
-      // OSX 10.7 bug fix, the menu won't appear without this.
-      // val is non-zero on other OSX versions.
+      // Mac OS X 10.7 bug fix, the menu won't appear without this.
+      // val is non-zero on other macOS versions.
       if (val == 0)
         {
           NSApplicationPresentationOptions options
@@ -7546,7 +7546,7 @@ not_in_argv (NSString *arg)
   unblock_input ();
 
   /*
-    drawRect: may be called (at least in OS X 10.5) for invisible
+    drawRect: may be called (at least in Mac OS X 10.5) for invisible
     views as well for some reason.  Thus, do not infer visibility
     here.
 
@@ -8071,7 +8071,7 @@ not_in_argv (NSString *arg)
   [self setEnabled: YES];
 
   /* Ensure auto resizing of scrollbars occurs within the emacs frame's view
-     locked against the top and bottom edges, and right edge on OS X, where
+     locked against the top and bottom edges, and right edge on macOS, where
      scrollers are on right. */
 #ifdef NS_IMPL_GNUSTEP
   [self setAutoresizingMask: NSViewMaxXMargin | NSViewHeightSizable];
@@ -8732,14 +8732,14 @@ allowing it to be used at a lower level for accented character entry.");
 
   DEFVAR_LISP ("ns-auto-hide-menu-bar", ns_auto_hide_menu_bar,
                doc: /* Non-nil means that the menu bar is hidden, but appears when the mouse is near.
-Only works on OSX 10.6 or later.  */);
+Only works on Mac OS X 10.6 or later.  */);
   ns_auto_hide_menu_bar = Qnil;
 
   DEFVAR_BOOL ("ns-use-native-fullscreen", ns_use_native_fullscreen,
-     doc: /*Non-nil means to use native fullscreen on OSX >= 10.7.
+     doc: /*Non-nil means to use native fullscreen on Mac OS X 10.7 and later.
 Nil means use fullscreen the old (< 10.7) way.  The old way works better with
-multiple monitors, but lacks tool bar.  This variable is ignored on OSX < 10.7.
-Default is t for OSX >= 10.7, nil otherwise.  */);
+multiple monitors, but lacks tool bar.  This variable is ignored on
+Mac OS X < 10.7.  Default is t for 10.7 and later, nil otherwise.  */);
 #ifdef HAVE_NATIVE_FS
   ns_use_native_fullscreen = YES;
 #else
@@ -8754,9 +8754,9 @@ Default is nil.  */);
   ns_use_fullscreen_animation = NO;
 
   DEFVAR_BOOL ("ns-use-srgb-colorspace", ns_use_srgb_colorspace,
-     doc: /*Non-nil means to use sRGB colorspace on OSX >= 10.7.
+     doc: /*Non-nil means to use sRGB colorspace on Mac OS X 10.7 and later.
 Note that this does not apply to images.
-This variable is ignored on OSX < 10.7 and GNUstep.  */);
+This variable is ignored on Mac OS X < 10.7 and GNUstep.  */);
   ns_use_srgb_colorspace = YES;
 
   /* TODO: move to common code */
diff --git a/src/sysdep.c b/src/sysdep.c
index 55d29bcc814..892e97626bd 100644
--- a/src/sysdep.c
+++ b/src/sysdep.c
@@ -2426,7 +2426,7 @@ posix_close (int fd, int flag)
      closed, and retrying the close could inadvertently close a file
      descriptor allocated by some other thread.  In other systems
      (e.g., HP/UX) FD is not closed.  And in still other systems
-     (e.g., OS X, Solaris), maybe FD is closed, maybe not, and in a
+     (e.g., macOS, Solaris), maybe FD is closed, maybe not, and in a
      multithreaded program there can be no way to tell.
 
      So, in this case, pretend that the close succeeded.  This works
diff --git a/src/unexmacosx.c b/src/unexmacosx.c
index ea8e884f177..5584e693f75 100644
--- a/src/unexmacosx.c
+++ b/src/unexmacosx.c
@@ -1,4 +1,4 @@
-/* Dump Emacs in Mach-O format for use on Mac OS X.
+/* Dump Emacs in Mach-O format for use on macOS.
    Copyright (C) 2001-2016 Free Software Foundation, Inc.
 
 This file is part of GNU Emacs.
@@ -24,7 +24,7 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
    Mach-O format: the file loader.h, man pages for Mach-O and ld, old
    NEXTSTEP documents of the Mach-O format.  The tool otool dumps the
    mach header (-h option) and the load commands (-l option) in a
-   Mach-O file.  The tool nm on Mac OS X displays the symbol table in
+   Mach-O file.  The tool nm on macOS displays the symbol table in
    a Mach-O file.  For examples of unexec for the Mach-O format, see
    the file unexnext.c in the GNU Emacs distribution, the file
    unexdyld.c in the Darwin port of GNU Emacs 20.7, and unexdyld.c in
@@ -33,7 +33,7 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
    Read that to see what they do.  This file was written completely
    from scratch, making use of information from the above sources.  */
 
-/* The Mac OS X implementation of unexec makes use of Darwin's `zone'
+/* The macOS implementation of unexec makes use of Darwin's `zone'
    memory allocator.  All calls to malloc, realloc, and free in Emacs
    are redirected to unexec_malloc, unexec_realloc, and unexec_free in
    this file.  When temacs is run, all memory requests are handled in
@@ -49,7 +49,7 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
    block must be obtained by malloc and the old contents copied to
    it.  */
 
-/* Peculiarity of the Mach-O files generated by ld in Mac OS X
+/* Peculiarity of the Mach-O files generated by ld in macOS
    (possible causes of future bugs if changed).
 
    The file offset of the start of the __TEXT segment is zero.  Since
@@ -117,9 +117,9 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 
 #include <assert.h>
 
-/* LC_DATA_IN_CODE is not defined in mach-o/loader.h on OS X 10.7.
+/* LC_DATA_IN_CODE is not defined in mach-o/loader.h on Mac OS X 10.7.
    But it is used if we build with "Command Line Tools for Xcode 4.5
-   (OS X Lion) - September 2012".  */
+   (Mac OS X Lion) - September 2012".  */
 #ifndef LC_DATA_IN_CODE
 #define LC_DATA_IN_CODE 0x29 /* table of non-instructions in __text */
 #endif
diff --git a/src/w32fns.c b/src/w32fns.c
index 1d83b02d629..8c8272b16d4 100644
--- a/src/w32fns.c
+++ b/src/w32fns.c
@@ -7328,7 +7328,7 @@ value of DIR as in previous invocations; this is standard Windows behavior.  */)
   } new_file_details_w;
 
 #ifdef NTGUI_UNICODE
-  wchar_t filename_buf_w[32*1024 + 1]; // NT kernel maximum
+  wchar_t filename_buf_w[32*1024 + 1]; /* NT kernel maximum */
   OPENFILENAMEW * file_details_w = &new_file_details_w.details;
   const int use_unicode = 1;
 #else /* not NTGUI_UNICODE */
diff --git a/src/xdisp.c b/src/xdisp.c
index 6e8af8aaf0a..c045ced000b 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -24565,7 +24565,7 @@ calc_pixel_width_or_height (double *res, struct it *it, Lisp_Object prop,
             }
           if (FRAME_WINDOW_P (it->f) && valid_xwidget_spec_p (prop))
             {
-              // TODO: Don't return dummy size.
+              /* TODO: Don't return dummy size.  */
               return OK_PIXELS (100);
             }
 #endif
diff --git a/src/xselect.c b/src/xselect.c
index 93b81b9fca1..b997cc887ef 100644
--- a/src/xselect.c
+++ b/src/xselect.c
@@ -693,7 +693,7 @@ x_reply_selection_request (struct selection_input_event *event,
                              : format_bytes);
             XFlush (display);
             had_errors_p = x_had_errors_p (display);
-            // See comment above about property_change_reply.
+            /* See comment above about property_change_reply.  */
             set_property_change_object (cs->wait_object);
             unblock_input ();
 
@@ -1393,7 +1393,7 @@ receive_incremental_selection (struct x_display_info *dpyinfo,
   wait_object = expect_property_change (display, window, property,
                                         PropertyNewValue);
   XFlush (display);
-  // See comment in x_reply_selection_request about property_change_reply.
+  /* See comment in x_reply_selection_request about property_change_reply.  */
   set_property_change_object (wait_object);
   unblock_input ();
 
@@ -1433,7 +1433,8 @@ receive_incremental_selection (struct x_display_info *dpyinfo,
       XDeleteProperty (display, window, property);
       wait_object = expect_property_change (display, window, property,
                                             PropertyNewValue);
-      // See comment in x_reply_selection_request about property_change_reply.
+      /* See comment in x_reply_selection_request about
+         property_change_reply.  */
       set_property_change_object (wait_object);
       XFlush (display);
       unblock_input ();
diff --git a/src/xsmfns.c b/src/xsmfns.c
index a7ec8e0c7e2..95ede642130 100644
--- a/src/xsmfns.c
+++ b/src/xsmfns.c
@@ -170,7 +170,7 @@ smc_save_yourself_CB (SmcConn smcConn,
   char *smid_opt, *chdir_opt = NULL;
   Lisp_Object user_login_name = Fuser_login_name (Qnil);
 
-  // Must have these.
+  /* Must have these.  */
   if (! STRINGP (Vinvocation_name) || ! STRINGP (user_login_name))
     return;
 
diff --git a/src/xterm.c b/src/xterm.c
index d6e1fe2190c..bdc21e6de02 100644
--- a/src/xterm.c
+++ b/src/xterm.c
@@ -12063,7 +12063,7 @@ x_term_init (Lisp_Object display_name, char *xrm_option, char *resource_name)
 
 #else /* not USE_X_TOOLKIT */
   XSetLocaleModifiers ("");
-  unrequest_sigio ();  // See comment in x_display_ok.
+  unrequest_sigio ();  /* See comment in x_display_ok.  */
   dpy = XOpenDisplay (SSDATA (display_name));
   request_sigio ();
 #endif /* not USE_X_TOOLKIT */