Two user-visible changes were made:
* `-DUSE_RUST` is replaced with `-DBUILD_RUST`, by analogy with
`-DBUILD_PYTHON`
* `-DCOVERAGE` was removed as it doesn't work with either modern GCC
or Clang
bel bindings should be updated with bindBel/unbindBel during placement, or setting the BEL attribute for constraints before placement.
Fixes#522
Signed-off-by: gatecat <gatecat@ds0.me>