cppdb: not available for static builds

Fixes:
http://autobuild.buildroot.net/results/cdc/cdc522c2cddb10a5c38239fcbea604bfa5a49045/

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/cppdb/Config.in

@@ -1,5 +1,7 @@
 config BR2_PACKAGE_CPPDB
 	bool "cppdb"
+	# dlfcn.h
+	depends on !BR2_PREFER_STATIC_LIB
 	depends on BR2_INSTALL_LIBSTDCPP
 	depends on BR2_TOOLCHAIN_HAS_THREADS
 	# Can be built without them but it's useless
@@ -11,6 +13,7 @@ config BR2_PACKAGE_CPPDB
 
 	  http://cppcms.com/sql/cppdb/
 
-comment "cppdb needs a toolchain w/ C++, threads"
+comment "cppdb needs a toolchain w/ C++, threads, dynamic library"
 	depends on BR2_PACKAGE_MYSQL || BR2_PACKAGE_SQLITE
-	depends on !BR2_INSTALL_LIBSTDCPP || !BR2_TOOLCHAIN_HAS_THREADS
+	depends on !BR2_INSTALL_LIBSTDCPP || !BR2_TOOLCHAIN_HAS_THREADS || \
+		BR2_PREFER_STATIC_LIB