rust/compiler/rustc_interface
Nicholas Nethercote c3c995a275 Handle build scripts better in -Zmacro-stats output.
Currently all build scripts are listed as `build_script_build` in the
stats header. This commit uses `CARGO_PKG_NAME` to improve that.

I tried it on Bevy, it works well, giving output like this on the build
script:
```
MACRO EXPANSION STATS: serde build script
```
and this on the crate itself:
```
MACRO EXPANSION STATS: serde
```
2025-06-30 16:32:00 +10:00
..
2025-03-30 01:32:21 +03:00