webrtc-audio-processing: needs threads

Fixes:
http://autobuild.buildroot.net/results/543/5435304b12fa1344411821b749cb028485431a82/

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

package/webrtc-audio-processing/Config.in

@@ -2,11 +2,12 @@ config BR2_PACKAGE_WEBRTC_AUDIO_PROCESSING
 	bool "webrtc-audio-processing"
 	depends on BR2_arm || BR2_i386 || BR2_x86_64
 	depends on BR2_INSTALL_LIBSTDCPP
+	depends on BR2_TOOLCHAIN_HAS_THREADS
 	help
 	  AudioProcessing library based on Google's implementation of
 	  WebRTC.
 
 	  http://freedesktop.org/software/pulseaudio/webrtc-audio-processing/
 
-comment "webrtc-audio-processing requires a toolchain with C++ support enabled"
-	depends on !BR2_INSTALL_LIBSTDCPP
+comment "webrtc-audio-processing requires a toolchain with C++ and thread support enabled"
+	depends on !(BR2_INSTALL_LIBSTDCPP && BR2_TOOLCHAIN_HAS_THREADS)