Revert "Work around RA's RUSTC_WRAPPER poisoning all subsequent comma…

…nd-line builds"

This reverts commit 77317b5.

Closes #261.

build.rs

@@ -65,9 +65,6 @@ fn main() {
 }
 
 fn compile_probe() -> Option<ExitStatus> {
-    // FIXME: obsoleted by https://github.com/rust-lang/cargo/pull/10973
-    println!("cargo:rerun-if-env-changed=RUSTC_WRAPPER");
-
     let rustc = env::var_os("RUSTC")?;
     let out_dir = env::var_os("OUT_DIR")?;
     let probefile = Path::new(&out_dir).join("probe.rs");