build: Set up dual install for flatpak

Part of https://gitlab.gnome.org/GNOME/Initiatives/issues/1;
Sets up dual installation for flatpaks, allowing us to
build and run geary without affecting our system install.
This will allow testing of nightlies and CI artifacts as well
via the flatpak, so we can iterate on designs and share
bundles to test with.

meson.build

@@ -1,7 +1,7 @@
 project('geary', [ 'vala', 'c' ],
   version: '3.33.1',
   license: 'LGPL2.1+',
-  meson_version: '>= 0.43',
+  meson_version: '>= 0.50',
 )
 
 gnome = import('gnome')
@@ -15,6 +15,25 @@ reference_tracking = get_option('ref_tracking')
 poodle = get_option('poodle')
 enable_valadoc = get_option('valadoc')
 
+# Build type
+if get_option('profile') == 'development'
+  name_suffix = ' (Development)'
+  profile = 'Devel'
+  vcs_tag = run_command('git', 'rev-parse', '--short', 'HEAD').stdout().strip()
+  if vcs_tag == ''
+    version_suffix = '-devel'
+  else
+    version_suffix = '-@0@'.format(vcs_tag)
+  endif
+else
+  profile = ''
+  name_suffix = ''
+  version_suffix = ''
+endif
+
+geary_id = 'org.gnome.Geary@0@'.format(profile)
+geary_version = meson.project_version() + version_suffix
+
 # Some variables
 cc = meson.get_compiler('c')
 valac = meson.get_compiler('vala')
@@ -187,12 +206,10 @@ conf.set_quoted('LANGUAGE_SUPPORT_DIRECTORY', locale_dir)
 conf.set_quoted('ISO_CODE_639_XML', iso_639_xml)
 conf.set_quoted('ISO_CODE_3166_XML', iso_3166_xml)
 conf.set('GCR_API_SUBJECT_TO_CHANGE', true)
-conf.set('HAVE_FTS3_TOKENIZE', true)
-# geary-version.vala.in gets configured twice (once for the version,
-# once for the revision), so make sure the revision template carries
-# through to the second time.
-conf.set('REVISION', '@REVISION@')
-conf.set('VERSION', meson.project_version())
+conf.set_quoted('_VERSION', geary_version)
+conf.set_quoted('_APP_ID', geary_id)
+conf.set_quoted('_PROFILE', profile)
+conf.set_quoted('_NAME_SUFFIX', name_suffix)
 configure_file(output: 'config.h', configuration: conf)
 
 # Post-install scripts