package/python-pyyaml: add cython for host-python-pyyaml

When migrating to setuptools with pep517 support we need to add
host-python-cython which is a pep517 build dependency for pyyaml.

Signed-off-by: James Hilliard <james.hilliard1@gmail.com>
[Arnout: order dependencies alphabetically]
Signed-off-by: Arnout Vandecappelle <arnout@mind.be>

package/python-pyyaml/python-pyyaml.mk

@@ -14,7 +14,8 @@ PYTHON_PYYAML_CPE_ID_VENDOR = pyyaml
 PYTHON_PYYAML_CPE_ID_PRODUCT = pyyaml
 PYTHON_PYYAML_DEPENDENCIES = host-python-cython libyaml
 PYTHON_PYYAML_ENV = PYYAML_FORCE_CYTHON=1
-HOST_PYTHON_PYYAML_DEPENDENCIES = host-libyaml
+HOST_PYTHON_PYYAML_DEPENDENCIES = host-libyaml host-python-cython
+HOST_PYTHON_PYYAML_ENV = PYYAML_FORCE_CYTHON=1
 
 $(eval $(python-package))
 $(eval $(host-python-package))