package/pulseaudio: disable doxygen

Disable doxygen which is enabled by default since bump to version 16.1
in commit 6f3131296484767f037d3535ab69f328e94351db:

../output-1/build/pulseaudio-16.1/doxygen/meson.build:9:0: ERROR: Program 'doxygen' not found or not executable

Fixes:
 - http://autobuild.buildroot.org/results/127b87f97eb5517cd0a513289768a599081c15c9

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>

package/pulseaudio/pulseaudio.mk

@@ -13,6 +13,7 @@ PULSEAUDIO_LICENSE_FILES = LICENSE GPL LGPL
 PULSEAUDIO_CPE_ID_VENDOR = pulseaudio
 PULSEAUDIO_SELINUX_MODULES = pulseaudio xdg
 PULSEAUDIO_CONF_OPTS = \
+	-Ddoxygen=false \
 	-Dlegacy-database-entry-format=false \
 	-Dman=false \
 	-Drunning-from-build-tree=false \