libroxml: needs threads

Fixes:
http://autobuild.buildroot.net/results/169/169b607993cd7ae4a8a79c2a00c00f820ec1c747/

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

package/libroxml/Config.in

@@ -1,8 +1,12 @@
 config BR2_PACKAGE_LIBROXML
 	bool "roxml"
+	depends on BR2_TOOLCHAIN_HAS_THREADS
 	help
 	  libroxml is a light and powerful xml parsing library with
 	  xpath handling. Roxml is a binary using libroxml to explore
 	  xml file from shell scripts.
 
 	  http://www.libroxml.net
+
+comment "libroxml needs a toolchain with thread support"
+	depends on !BR2_TOOLCHAIN_HAS_THREADS