Introduce a build-time pass that tags every QEMU helper transitively
reaching a function defined under one of the configured runtime-library
directories (currently `fpu/` only) as `revng_inline`. The intent is to
make the lift pipeline surface "leaf-level" runtime-library calls (e.g.
softfloat ops) directly in the lifted IR by inlining away every wrapper
helper that sits between QEMU's `helper_*` boundary and the leaf.
We also gate the tagging by a per-function body-size budget.
The pass is run in the pipeline building the `libtcg-helpers-full-*.bc`
artifacts.
Andrea Gussoni