Both HAVE_OSS_OUTPUT and HAVE_SOLARIS are defined in pulseaudio
This problem only shows up when the system has two sound devices, and AUDIODEV is used to specify that the second sound device is desired. In this case, the environment variable AUDIODEV will contain /dev/sound/1 . This condition is examined in the detect_solaris() function of pulseaudio-11.1/src/modules/module-detect.c, included when the symbol HAVE_SOLARIS is defined. However, if the symbol HAVE_OSS_OUTPUT is also defined, the function detect_oss() is also included. This function ignores the AUDIODEV environment variable as well as /dev/audio, using instead the device /dev/dsp, which also exists in illumos and OI. The result is that the first sound device will always be used, regardless of AUDIODEV or /dev/audio . OSS seems to mean only Linux and FreeBSD for configuration purposes.
The cause is the statement `CONFIGURE_OPTIONS += --enable-oss-output' in the OI Makefile. When this is changed to `CONFIGURE_OPTIONS += --disable-oss-output', the module module-detect.so will only include the detect_solaris() function.