gst1-validate: needs python

If host installed python version is < 2.7.0 gst1-validate compile will fail with

	checking for a Python interpreter with version >= 2.7.0... none
	configure: error: no suitable Python interpreter found

Fixed by adding host-python dependency.

Target tool /usr/bin/gst-validate-launcher is a python2 script

	$ head -1 /usr/bin/gst-validate-launcher
	#!/usr/bin/env python2

(and not easily upgradable to python3) so add python2 dependency and to fix
the following runtime error

	$ gst-validate-launcher
	Traceback (most recent call last):
	  File "/usr/bin/gst-validate-launcher", line 44, in <module>
	    from launcher.main import main
	  File "/usr/lib/gst-validate-launcher/python/launcher/main.py", line 26, in <module>
	    import reporters
	  File "/usr/lib/gst-validate-launcher/python/launcher/reporters.py", line 29, in <module>
	    from xml.sax import saxutils
	ImportError: No module named xml.sax

add additional BR2_PACKAGE_PYTHON_PYEXPAT select.

Fixes:
 http://autobuild.buildroot.net/results/e8c/e8c27db2a0935c2daef173d5650f6a2b3a219493/
 http://autobuild.buildroot.net/results/723/723fe3036e8f0af2a90ff9e98173387466655000/

Signed-off-by: Peter Seiderer <ps.report@gmx.net>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/gstreamer1/gst1-validate/Config.in

@@ -1,9 +1,14 @@
-menuconfig BR2_PACKAGE_GST1_VALIDATE
+config BR2_PACKAGE_GST1_VALIDATE
 	bool "gst1-validate"
+	depends on BR2_PACKAGE_PYTHON
 	select BR2_PACKAGE_GST1_PLUGINS_BASE
+	select BR2_PACKAGE_PYTHON_PYEXPAT
 	help
 	  GstValidate is a tool that allows GStreamer developers to
 	  check that the GstElements they write behave the way they
 	  are supposed to.
 
 	  http://gstreamer.freedesktop.org/
+
+comment "gst1-validate depends on python"
+	depends on !BR2_PACKAGE_PYTHON

package/gstreamer1/gst1-validate/gst1-validate.mk

@@ -12,6 +12,6 @@ GST1_VALIDATE_LICENSE_FILES = COPYING
 
 GST1_VALIDATE_CONF_OPTS = --disable-sphinx-doc
 
-GST1_VALIDATE_DEPENDENCIES = gstreamer1 gst1-plugins-base
+GST1_VALIDATE_DEPENDENCIES = gstreamer1 gst1-plugins-base host-python python
 
 $(eval $(autotools-package))