-Dpulse= is derived with $(if $(CONFIG_PACKAGE_audio-support)), true for
=m as well, while the rpath-link that lets the linker find
libpulsecommon was guarded by ifeq(...,y). Selecting audio-support as a
module built pulse support without the flag, leaving every pa_* symbol
undefined. Test the same way the option does.
Signed-off-by: Alexandru Ardelean <alex@shruggie.ro>