package/perl-xml-libxml: not available for static link

Perl extensions are loaded at runtime with dlopen(), so it does not
make sense to even build extensions that are written in C.

perl-xml-libxml is written in C, so it is not available when doing a
static build.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Francois Perrad <francois.perrad@gadz.org>
Cc: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/perl-xml-libxml/Config.in

@@ -1,5 +1,6 @@
 config BR2_PACKAGE_PERL_XML_LIBXML
 	bool "perl-xml-libxml"
+	depends on !BR2_PREFER_STATIC_LIB
 	select BR2_PACKAGE_LIBXML2
 	select BR2_PACKAGE_ZLIB
 	select BR2_PACKAGE_PERL_XML_NAMESPACESUPPORT
@@ -8,3 +9,6 @@ config BR2_PACKAGE_PERL_XML_LIBXML
 	  Interface to Gnome libxml2 xml parsing and DOM library
 
 	  https://bitbucket.org/shlomif/perl-xml-libxml
+
+comment "perl-xml-libxml needs a toolchain w/ dynamic library"
+	depends on BR2_PREFER_STATIC_LIB