package/file: add xz optional dependency

xz is an optional dependency since version 5.38 and
https://github.com/file/file/commit/b259a07ea95827f565faa20f0316e5b2704064f7

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/file/file.mk

@@ -21,5 +21,12 @@ else
 FILE_CONF_OPTS += --disable-libseccomp
 endif
 
+ifeq ($(BR2_PACKAGE_XZ),y)
+FILE_CONF_OPTS += --enable-xzlib
+FILE_DEPENDENCIES += xz
+else
+FILE_CONF_OPTS += --disable-xzlib
+endif
+
 $(eval $(autotools-package))
 $(eval $(host-autotools-package))