Summary:
Currently when building PyTorch with latest RocksDB we get errors like "missing target Snappy::snappy", because they are simply not there.
With old `${VAR}` approach we essentially hard-code the abs path found during RocksDB build, which is:
- Not relocatable.
- Doesn't work when changed to modern target-based design because that requires target to present when used for expansion.
This fix allows cmake to setup imported target, if enabled during RocksDB build, when downstream uses `find_package(RocksDB)`.
This is for https://github.com/facebook/rocksdb/issues/6179
tchaikov Please help review, thanks!
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6791
Reviewed By: riversand963
Differential Revision: D21471553
fbshipit-source-id: 8d4ff2ab589a97ca6e6ba27e1f17b97a00f06206