open-lldp: requires dynamic linking interface (dlopen, ...)

Fixes:
http://autobuild.buildroot.net/results/516456c8e21759e1ecee4ef9f9689a8f720ecd90/

This patch is to fix the following build error:
weak_readline.c:30:19: fatal error: dlfcn.h: No such file or directory
 #include <dlfcn.h>
                   ^
compilation terminated.
Makefile:890: recipe for target 'weak_readline.o' failed

Signed-off-by: Laurent Charpentier <laurent_pubs@yahoo.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/open-lldp/Config.in

@@ -1,5 +1,6 @@
 config BR2_PACKAGE_OPEN_LLDP
 	bool "open-lldp"
+	depends on !BR2_STATIC_LIBS # dlfcn.h
 	depends on BR2_TOOLCHAIN_HAS_THREADS # libnl
 	select BR2_PACKAGE_LIBCONFIG
 	select BR2_PACKAGE_LIBNL
@@ -11,5 +12,5 @@ config BR2_PACKAGE_OPEN_LLDP
 
 	  http://open-lldp.org/
 
-comment "open-lldp needs a toolchain w/ threads"
-	depends on !BR2_TOOLCHAIN_HAS_THREADS
+comment "open-lldp needs a toolchain w/ dynamic library, threads"
+	depends on BR2_STATIC_LIBS || !BR2_TOOLCHAIN_HAS_THREADS