+ (let ((arch (with-temp-buffer
+ (when (eq 0 (ignore-errors
+ (call-process "gcc" nil '(t nil) nil
+ "-print-multiarch")))
+ (goto-char (point-min))
+ (buffer-substring (point) (line-end-position)))))
+ (base '("/usr/include" "/usr/local/include")))
+ (if (zerop (length arch))
+ base
+ (append base (list (expand-file-name arch "/usr/include")))))
+ "List of directories to search for include files.")
+