libkrb5: needs dynamic library support

Even though the configure script checks for the presence of dlfcn.h, the
code includes this header unconditionally.

Fixes:
http://autobuild.buildroot.net/results/0e1/0e19af38d74aa74919a11ff1ebdb3b8c1a494b33/

Cc: André Hentschel <nerv@dawncrow.de>
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/libkrb5/Config.in

@@ -2,6 +2,7 @@ config BR2_PACKAGE_LIBKRB5
 	bool "libkrb5"
 	# needs fork()
 	depends on BR2_USE_MMU
+	depends on !BR2_STATIC_LIBS
 	help
 	  Kerberos is a system for authenticating users and services
 	  on a network. Kerberos is a trusted third-party service.
@@ -11,3 +12,7 @@ config BR2_PACKAGE_LIBKRB5
 	  reference implementation of Kerberos V5.
 
 	  https://web.mit.edu/kerberos/
+
+comment "libkrb5 needs a toolchain w/ dynamic library"
+	depends on BR2_USE_MMU
+	depends on BR2_STATIC_LIBS