botan: requires a toolchain with threads

fixes http://autobuild.buildroot.org/results/3df/3dfc002d8c19001dea4f13aa06cc6ec3f65fc4cb/

Signed-off-by: Francois Perrad <francois.perrad@gadz.org>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/botan/Config.in

@@ -8,12 +8,13 @@ config BR2_PACKAGE_BOTAN_ARCH_SUPPORTS
 config BR2_PACKAGE_BOTAN
 	bool "botan"
 	depends on BR2_INSTALL_LIBSTDCPP
+	depends on BR2_TOOLCHAIN_HAS_THREADS
 	depends on BR2_PACKAGE_BOTAN_ARCH_SUPPORTS
 	help
 	  Botan is a crypto library for C++
 
 	  http://botan.randombit.net
 
-comment "botan needs a toolchain w/ C++"
-	depends on !BR2_INSTALL_LIBSTDCPP
+comment "botan needs a toolchain w/ C++, threads"
+	depends on !BR2_TOOLCHAIN_HAS_THREADS || !BR2_INSTALL_LIBSTDCPP
 	depends on BR2_PACKAGE_BOTAN_ARCH_SUPPORTS