Change the font detection and add logs

core/core-fonts-support.el

@@ -23,6 +23,7 @@ PLIST has the form (\"fontname\" :prop1 val1 :prop2 val2 ...)"
                       (spacemacs/mplist-remove props :powerline-scale)
                       :powerline-offset))
          (fontspec (apply 'font-spec :family font font-props)))
+    (spacemacs/message "Setting font \"%s\"..." font)
     (set-default-font fontspec nil t)
     (setq-default powerline-scale scale)
     (setq-default powerline-height (spacemacs/compute-powerline-height))

core/core-spacemacs-mode.el

@@ -90,8 +90,10 @@
                                "able to launch a graphical instance of Emacs"
                                "with this build.")))
   ;; font
-  (when (member (car dotspacemacs-default-font) (font-family-list))
-    (spacemacs/set-default-font dotspacemacs-default-font))
+  (if (find-font (font-spec :name (car dotspacemacs-default-font)))
+      (spacemacs/set-default-font dotspacemacs-default-font)
+    (spacemacs/message "Warning: Cannot find font \"%s\"!"
+                       (car dotspacemacs-default-font)))
   ;; banner
   (spacemacs//insert-banner)
   ;; bind-key is required by use-package