modules: Provide an alias for module-rtkit

So this will now use `module-rt` even with old configurations that still
use `module-rtkit`.

src/modules/meson.build

@@ -145,6 +145,20 @@ pipewire_module_rt = shared_library('pipewire-module-rt', [ 'module-rt.c' ],
   install_rpath: modules_install_dir,
   dependencies : [dbus_dep, mathlib, dl_lib, pipewire_dep],
 )
+# TODO: This serves as a temporary alias to prevent breaking existing setups
+#       while `module-rtkit` is being migrated to `module-rt`
+fs = import('fs')
+custom_target('pipewire-module-rtkit',
+  # Basing this on the original output path makes sure we get the library
+  # prefixes and suffixes right
+  output : [fs.name(pipewire_module_rt.full_path()).replace('module-rt', 'module-rtkit')],
+  # Using the `input` parameter for this doesn't work on Meson 59, and on newer
+  # versions it will show a spurious warning
+  command : ['ln', '-sf', fs.name(pipewire_module_rt.full_path()), '@OUTPUT@'],
+  install : true,
+  install_dir : modules_install_dir,
+  depends : [pipewire_module_rt],
+)
 endif
 summary({'rt': build_module_rt}, bool_yn: true, section: 'Optional Modules')