libtool archives introduce unwanted inputs to build

[宋文武]

Report by Jookia in #guix that with my gdk-pixbuf+svg patches,
thunar still can't find SVG icons, it's linked with the old gdk-pixbuf.

While the build inputs of ‘thunar’ only have ‘gdk-pixbuf+svg’, one
of its input ‘libnotify’ was build with ‘gdk-pixbuf’.  It didn’t
propagated it but it’s in ‘libnotify.la’.

Remove ‘gdk-pixbuf’ from libnotify’s inputs or the ‘libnotify.la’ file
will fix thunar.

So libtool archives are the hidden propagated-inputs, maybe we should
remove them all?