package/setools: install for host-python3

setools needs python3 since version 4.2.0 and
https://github.com/SELinuxProject/setools/commit/e292a77c52ed882707c8d165e77914837367313f

However today in Buildroot, when no target python is selected, or when
BR2_PACKAGE_PYTHON=y, all host python modules are installed for
host-python, i.e Python 2. But this module won't install in Python 2,
so let's force its host variant to be installed with Python 3 on the
host. Of course, for that to work, its dependency must also be built
for host-python3, so we change it to the newly introduced
host-python3-cython package.

Fixes:
 - http://autobuild.buildroot.org/results/c2febcea5fbd8a21709721524ae9e9b5fc0896f9

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

package/setools/Config.in

@@ -4,7 +4,7 @@ config BR2_PACKAGE_SETOOLS
 	depends on BR2_TOOLCHAIN_HAS_THREADS
 	depends on BR2_USE_WCHAR
 	depends on BR2_USE_MMU
-	depends on BR2_PACKAGE_PYTHON3 # python-networkx
+	depends on BR2_PACKAGE_PYTHON3
 	select BR2_PACKAGE_PYTHON_NETWORKX # runtime
 	select BR2_PACKAGE_PYTHON_SETUPTOOLS
 	select BR2_PACKAGE_LIBSELINUX

package/setools/setools.mk

@@ -11,7 +11,8 @@ SETOOLS_INSTALL_STAGING = YES
 SETOOLS_LICENSE = GPL-2.0+, LGPL-2.1+
 SETOOLS_LICENSE_FILES = COPYING COPYING.GPL COPYING.LGPL
 SETOOLS_SETUP_TYPE = setuptools
-HOST_SETOOLS_DEPENDENCIES = host-python-cython host-libselinux host-libsepol host-python-networkx
+HOST_SETOOLS_DEPENDENCIES = host-python3-cython host-libselinux host-libsepol host-python-networkx
+HOST_SETOOLS_NEEDS_HOST_PYTHON = python3
 
 define SETOOLS_FIX_SETUP
 	# By default, setup.py will look for libsepol.a in the host machines