GENERATED files can be used as dependencies for other targets, so it's
misguided (at best) to filter them with a blunt whitelist.
However, there does exist an extension that needs to be skipped: on Windows +
MSVC, CMake will by default try to generate a Visual Studio project, and
there dependencies with no inputs are instead tied to a dummy .rule
input file which is created by the generation step. The fileapi will
still report those, so it will cause Meson to bail out when it realises
there's no such file in the build tree.
Fixes#11607