botan: disable for static builds

it tries to include <dlfcn.h>

see http://autobuild.buildroot.net/results/2d1/2d1563e253b669b45c9df449c5b3a750c04a43dc/

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

package/botan/Config.in

@@ -10,11 +10,12 @@ config BR2_PACKAGE_BOTAN
 	depends on BR2_INSTALL_LIBSTDCPP
 	depends on BR2_TOOLCHAIN_HAS_THREADS
 	depends on BR2_PACKAGE_BOTAN_ARCH_SUPPORTS
+	depends on !BR2_PREFER_STATIC_LIB # dlfcn.h
 	help
 	  Botan is a crypto library for C++
 
 	  http://botan.randombit.net
 
-comment "botan needs a toolchain w/ C++, threads"
-	depends on !BR2_TOOLCHAIN_HAS_THREADS || !BR2_INSTALL_LIBSTDCPP
+comment "botan needs a toolchain w/ C++, threads, dynamic library"
+	depends on !BR2_TOOLCHAIN_HAS_THREADS || !BR2_INSTALL_LIBSTDCPP || BR2_PREFER_STATIC_LIB
 	depends on BR2_PACKAGE_BOTAN_ARCH_SUPPORTS