data: Add polkit policy description

Describe and set defaults for claiming sensors.

data/meson.build

@@ -20,3 +20,18 @@ configure_file(
   configuration: data_conf,
   install_dir: dbusconfdir
 )
+
+polkit_policy = 'net.hadess.SensorProxy.policy'
+if xmllint.found()
+  test(polkit_policy,
+       xmllint,
+       args: [
+           '--noout',
+           meson.source_root() / 'data' / polkit_policy,
+       ])
+endif
+
+install_data(
+  polkit_policy,
+  install_dir: polkit_policy_directory,
+)

data/net.hadess.SensorProxy.policy

@@ -0,0 +1,21 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE policyconfig PUBLIC
+ "-//freedesktop//DTD PolicyKit Policy Configuration 1.0//EN"
+ "http://www.freedesktop.org/standards/PolicyKit/1.0/policyconfig.dtd">
+
+<policyconfig>
+
+  <vendor>iio-sensor-proxy</vendor>
+  <vendor_url>https://gitlab.freedesktop.org/hadess/iio-sensor-proxy</vendor_url>
+
+  <action id="net.hadess.SensorProxy.claim-sensor">
+    <description>Claim Access to a Sensor</description>
+    <message>Privileges are required to claim a sensor.</message>
+    <defaults>
+      <allow_any>no</allow_any>
+      <allow_inactive>no</allow_inactive>
+      <allow_active>yes</allow_active>
+    </defaults>
+  </action>
+
+</policyconfig>

meson.build

@@ -45,6 +45,8 @@ endif
 gio_dep = dependency('gio-2.0')
 gudev_dep = dependency('gudev-1.0', version: '>= 237')
 
+xmllint = find_program('xmllint', required: false)
+
 gnome = import('gnome')
 
 add_global_arguments('-D_GNU_SOURCE=1', language: 'c')