Adopted from Michael Beer -- GH pull-request #232 with minor changes:
* rebased on master,
* removed trailing whitespace,
* don't explicitly change saved configuration defaults (wscript)
* moved sys/wait (WNOHANG) to header include
* separate changes in GUI and lib
(may need further cleanup:
compare with timbyr's windows patch,
verify fst/vsti + ALSA)
git-svn-id: svn://localhost/ardour2/branches/3.0@13774 d708f5d6-7413-0410-9779-e7cbd77b26cf