Rollup merge of #42985 - venkatagiri:issue_42444, r=Mark-Simulacrum

rustc_llvm: re-run build script when env var LLVM_CONFIG changes

This removes the changes done in #42429 and use the newly introduced `cargo:rerun-if-env-changed` in https://github.com/rust-lang/cargo/pull/4125.
As `LLVM_CONFIG` env var points to the `llvm-config` and changes when it gets configured in `config.toml` or removed from it, we can re-run the build script if this env var changes.

closes #42444

r? @alexcrichton

1 files changed, 0 insertions, 4 deletions

diff --git a/src/bootstrap/compile.rs b/src/bootstrap/compile.rs
index c8ab3a8fc1d..b2bd792e93b 100644
--- a/src/bootstrap/compile.rs
+++ b/src/bootstrap/compile.rs
@@ -276,10 +276,6 @@ pub fn rustc(build: &Build, target: &str, compiler: &Compiler) {
     if build.is_rust_llvm(target) {
         cargo.env("LLVM_RUSTLLVM", "1");
     }
-    if let Some(ref cfg_file) = build.flags.config {
-        let cfg_path = t!(PathBuf::from(cfg_file).canonicalize());
-        cargo.env("CFG_LLVM_TOML", cfg_path.into_os_string());
-    }
     cargo.env("LLVM_CONFIG", build.llvm_config(target));
     let target_config = build.config.target_config.get(target);
     if let Some(s) = target_config.and_then(|c| c.llvm_config.as_ref()) {