When I try to use realtime output for csound 5.07 (which I just built
and installed) I receive '*** error: unknown rtaudio module: 'alsa'.

OPCODEDIR64 is set to /usr/lib/csound/plugins64 and CSSTRNGS is set to
/usr/share/xmg as suggested after running install.py.

According to scons ALSA, PortAudio and JACK plugins/modules are built.

Does anyone know why this is caused? It happened with Csound5.06 and
5.07 either running csound in the build directory or /usr/bin/csound
post-install.

Thank you for reading,
Glen Kirkup