host-python: enable expat support

Some packages (like libxcb) need xml support in host-python in order to
build (.py file tries to import xml.etree.cElementTree).

Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

package/python/python.mk

@@ -18,7 +18,7 @@ HOST_PYTHON_CONF_OPT += 	\
 	--without-cxx-main 	\
 	--disable-sqlite3	\
 	--disable-tk		\
-	--with-expat=none	\
+	--with-expat=system	\
 	--disable-curses	\
 	--disable-codecs-cjk	\
 	--disable-nis		\
@@ -39,6 +39,8 @@ HOST_PYTHON_AUTORECONF = YES
 
 PYTHON_DEPENDENCIES  = host-python libffi
 
+HOST_PYTHON_DEPENDENCIES = host-expat
+
 PYTHON_INSTALL_STAGING = YES
 
 ifeq ($(BR2_PACKAGE_PYTHON_READLINE),y)