Created attachment 198997 [details]
patch to pkg-plist that conditionalizes ALSA and PULSEAUDIO options.
# This file is auto-generated by 'make config'.
# Options for qt5-multimedia-5.12.0.b3_1
_FILE_COMPLETE_OPTIONS_LIST=GSTREAMER OPENAL ALSA PULSEAUDIO
Attached patch allows me to compile with PULSEAUDIO by adjusting pkg-plist to only search for ALSA and PULSEAUDIO files if their respective options are selected during configuration.
Ahhhh, you are using one of the branches on github, that explains why I could not reproduce it in ports :D
Let me quickly fix it at the right place.
It is fixed now in branches/qt5-5.12 and branches/plasma5-5.13