build: Use gnome.post_install

Also requires meson 0.57.0.
Otherwise the post install script will fail if GTK 3 is not installed.

build-aux/meson.build

@@ -1 +0,0 @@
-subdir('meson')

build-aux/meson/meson.build

@@ -1 +0,0 @@
-meson.add_install_script('meson_post_install.py')

build-aux/meson/meson_post_install.py

@@ -1,15 +0,0 @@
-#!/usr/bin/env python3
-
-import os
-import subprocess
-
-install_prefix = os.environ['MESON_INSTALL_PREFIX']
-icondir = os.path.join(install_prefix, 'share', 'icons', 'hicolor')
-schemadir = os.path.join(install_prefix, 'share', 'glib-2.0', 'schemas')
-
-if not os.environ.get('DESTDIR'):
-  print('Update icon cache...')
-  subprocess.call(['gtk-update-icon-cache', '-f', '-t', icondir])
-
-  print('Compiling gsettings schemas...')
-  subprocess.call(['glib-compile-schemas', schemadir])