Add a default value for kbd-mac-command

CHANGELOG.develop

@@ -2066,6 +2066,8 @@ Other:
   - Added ~M-s-h~ to hide other windows (thanks to Bas Veeling)
 - Replace pbcopy by osx-clipboard (thanks to Minh Nguyen-Hue)
 - Fixed key binding issue when Emacs is launched in daemon mode.
+- Added the default value =H-= (hyper) to =kbd-mac-command= if it's neither:
+  =hyper=, =super= or =alt= (thanks to Binbin Ye)
 **** Pandoc
 - Fixed =spacemacs/run-pandoc= not to reset =pandoc--local-settings=
   (thanks to martian-f)

layers/+os/osx/keybindings.el

@@ -52,13 +52,15 @@ such as \"H-f\", \"s-f\", or \"A-f\" depending on the value of
 `mac-commmand-modifier' which could be `hyper', `super', or `alt'.
 KEYS with a string of \"C-f\" are also valid and will be turned into
 values such as \"H-C-f\".
-Returns nil if `mac-command-modifier' is set to `none' or something
-other than the three sane values listed above."
+if `mac-command-modifier' is set to `none' or something other than
+the three sane values listed above, bind to `H-' by default"
     (let ((found (assoc mac-command-modifier
                         '((hyper . "H-")
                           (super . "s-")
                           (alt   . "A-")))))
-      (when found (kbd (concat (cdr found) keys)))))
+      (if found
+          (kbd (concat (cdr found) keys))
+        (kbd (concat "H-" keys)))))
 
   ;; Keybindings
   (global-set-key (kbd-mac-command "=") 'spacemacs/scale-up-font)