Removes liconv LDFLAG and fixes ICONV_FULL.

Signed-off-by: Rosen Penev <rosenp@gmail.com>

pulseaudio-daemon depends on alsa-lib, which depends on @AUDIO_SUPPORT.
Enables -full on platforms lacking AUDIO_SUPPORT.

Simplified LDFLAGS slighly.

Removed pointless ICU dependency. I managed to patch meson.build to fix
iconv compilation. The original error was that without the header, it
was prefixing the iconv check with __buildin_ , which does not work
with uClibc-ng.

Signed-off-by: Rosen Penev <rosenp@gmail.com>