speedbar-fetch-etags-arguments

speedbar-fetch-etags-arguments is a variable defined in `speedbar.el'.
Its value is

("-D" "-I" "-o" "-")

Documentation:
List of arguments to use with `speedbar-fetch-etags-command'.
This creates an etags output buffer. Use `speedbar-toggle-etags' to
modify this list conveniently.
This variable is ignored if `speedbar-use-imenu-flag' is t.

You can customize this variable.