avahi: needs threads

Fixes:
http://autobuild.buildroot.net/results/bc64cd3499d7c3c674e8e79b749ff96a756852ea/

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

package/avahi/Config.in

@@ -2,6 +2,7 @@ config BR2_PACKAGE_AVAHI
 	bool "avahi"
 	# libdaemon uses fork()
 	depends on BR2_USE_MMU
+	depends on BR2_TOOLCHAIN_HAS_THREADS
 	select BR2_PACKAGE_GETTEXT if BR2_NEEDS_GETTEXT_IF_LOCALE
 	help
 	  Avahi is a system which facilitates service
@@ -32,3 +33,6 @@ config BR2_PACKAGE_AVAHI_DAEMON
 	  architecture (also known as "Rendezvous" or "Bonjour").
 	  The daemon registers local IP addresses and services using
 	  mDNS/DNS-SD.
+
+comment "avahi requires a toolchain with thread support"
+	depends on !BR2_TOOLCHAIN_HAS_THREADS