package/mdadm: not available in static builds

http://git.neil.brown.name/?p=mdadm.git;a=commitdiff;h=7716570e6d906e7326f83d466f6ba73009649d03#patch9
added code to include dlfcn.h.

Fixes
http://autobuild.buildroot.net/results/163/163ad5a9f976662be8ca8664f91254f90fca8439/

Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>

package/mdadm/Config.in

@@ -1,7 +1,12 @@
 config BR2_PACKAGE_MDADM
 	bool "mdadm"
+	depends on !BR2_STATIC_LIBS # dlfcn.h
 	depends on BR2_USE_MMU # fork()
 	help
 	  Utility for managing Linux Software RAID arrays.
 
 	  http://neil.brown.name/blog/mdadm
+
+comment "mdadm needs a toolchain w/ dynamic library"
+	depends on BR2_STATIC_LIBS
+	depends on BR2_USE_MMU