libraries/libmp3splt: Added --docdir configure parameter.
libraries/libmp3splt: Added --docdir configure parameter.

Signed-off-by: Heinz Wiesinger <448437a28bf2be3473405344635ac3831c7b532b@slackbuilds.org>

panosmdma/SlackOnly-SlackBuilds,panosmdma/SlackOnly-SlackBuilds,panosmdma/SlackOnly-SlackBuilds,panosmdma/SlackOnly-SlackBuilds,panosmdma/SlackOnly-SlackBuilds,panosmdma/SlackOnly-SlackBuilds,panosmdma/SlackOnly-SlackBuilds