Fix an issue with -DTG_OWT_USE_PIPEWIRE=OFF

Some files were erroneously being included despite the option being turned off

--- tg_owt-91d836dc84a16584c6ac52b36c04c0de504d9c34.orig/CMakeLists.txt
+++ tg_owt-91d836dc84a16584c6ac52b36c04c0de504d9c34/CMakeLists.txt
@@ -88,6 +88,7 @@
 init_target(tg_owt)
 
 if (TG_OWT_USE_PIPEWIRE)
+    link_glib(tg_owt)
     if (TG_OWT_DLOPEN_PIPEWIRE)
         include(cmake/generate_stubs.cmake)
         set(stubs_loc ${webrtc_loc}/modules/desktop_capture/linux)
@@ -169,7 +170,6 @@
 
 if (UNIX AND NOT APPLE)
     link_x11(tg_owt)
-    link_glib(tg_owt)
 endif()
 
 function(add_sublibrary postfix)
@@ -2161,6 +2161,13 @@
     )
 endif()
 
+if (NOT TG_OWT_USE_PIPEWIRE)
+    remove_target_sources(tg_owt ${webrtc_loc}
+        modules/desktop_capture/linux/base_capturer_pipewire.cc
+        modules/desktop_capture/linux/base_capturer_pipewire.h
+    )
+endif()
+
 if (NOT TG_OWT_BUILD_AUDIO_BACKENDS)
     remove_target_sources(tg_owt ${webrtc_loc}
         rtc_base/win/windows_version.cc