poco: needs threads

Fixes
http://autobuild.buildroot.net/results/98f8ae541939bd7b44601d3ee039bbc84becea84.

Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

package/poco/Config.in

@@ -2,6 +2,7 @@ config BR2_PACKAGE_POCO
 	bool "poco"
 	depends on BR2_INSTALL_LIBSTDCPP
 	depends on BR2_USE_WCHAR
+	depends on BR2_TOOLCHAIN_HAS_THREADS
 	select BR2_PACKAGE_ZLIB
 	select BR2_PACKAGE_PCRE
 	help
@@ -57,5 +58,6 @@ config BR2_PACKAGE_POCO_DATA_MYSQL
 
 endif # BR2_PACKAGE_POCO
 
-comment "poco requires a toolchain with WCHAR and C++ support"
-	depends on !BR2_USE_WCHAR || !BR2_INSTALL_LIBSTDCPP
+comment "poco requires a toolchain with WCHAR, threads, and C++ support"
+	depends on !BR2_USE_WCHAR || !BR2_INSTALL_LIBSTDCPP \
+		|| !BR2_TOOLCHAIN_HAS_THREADS