gdk_threads_* deprecation warnings on build

When building xfburn from commit 67388ba6 using GTK 3.24.25, deprecation warnings are emitted concerning:

• void gdk_threads_init(void)
• void gdk_threads_enter(void)
• void gdk_threads_leave(void)

This is the warning I see in the documentation for each:

" has been deprecated since version 3.6 and should not be used in newly-written code. All GDK and GTK+ calls should be made from the main thread"

I am not familiar with the GDK Threads API, so I am unsure what a fix for these deprecation warnings would look like.

Full build output: build-output.txt