i need manual install flvtool2 because install by apt is not available anymore for flvtool2.
then i install ruby before compile flvtool2. succeed. i got ruby version 2.3.1p112.

when i run:
$ruby setup.rb config

i got these message:

setup.rb:283: warning: key "bin-dir" is duplicated and overwritten on line 284
setup.rb:788:in load_rbconfig: uninitialized constant Config (NameError)
Did you mean? RbConfig
from setup.rb:768:in invoke
from setup.rb:1578:in <main>

how to compile flvtool correctly?