debian: Wrap squeekboard in theme selector

This works around https://source.puri.sm/Librem5/squeekboard/issues/151 by providing a dark style to match the dark style of the layouts.

src/meson.build

@@ -95,7 +95,20 @@ libsqueekboard = static_library('libsqueekboard',
     '-DEEK_COMPILATION=1'],
 )
 
-squeekboard = executable('squeekboard',
+# the straight binary needs to be demoted in favor of the wrapper script
+# due to styling being inconsistent
+bindir = join_paths(prefix, get_option('bindir'))
+wrapper_conf = configuration_data()
+wrapper_conf.set('bindir', bindir)
+configure_file(
+  input: '../tools/squeekboard.in',
+  output: 'squeekboard',
+  install_dir: bindir,
+  configuration: wrapper_conf,
+  install: true,
+)
+
+squeekboard = executable('squeekboard-real',
   'server-main.c',
   wl_proto_sources,
   squeekboard_resources,