[llvm] [LLVM] Automatically strip `-fno-lifetime-dse` from compile_commands.json (PR #124623)

[Petr Hosek via llvm-commits]

petrhosek wrote:

I don't understand the issue, the `command` field for each file in the compilation database should include a full compiler invocation, so if you merge compilation database from both the LLVM and runtime builds, so you should end up with something like:
```
[
  ...
  {
    "command": "/usr/bin/g++ ... -fno-lifetime-dse",
    ...
  },
  ...
  {
    "command": "/path/to/build/bin/clang ...",
    ...
  },
  ...
]
```

It sounds like you also end up with `/path/to/build/bin/clang ... -fno-lifetime-dse` entries in the database. Where does it come from?

https://github.com/llvm/llvm-project/pull/124623