build: Remove unnecessary cargo:rerun-if-env-changed annotations

Author: petrochenkov

src/librustc_ast/build.rs

@@ -163,7 +163,7 @@ fn main() {
         cfg.define(&flag, None);
     }
 
-    println!("cargo:rerun-if-changed-env=LLVM_RUSTLLVM");
+    println!("cargo:rerun-if-env-changed=LLVM_RUSTLLVM");
     if env::var_os("LLVM_RUSTLLVM").is_some() {
         cfg.define("LLVM_RUSTLLVM", None);
     }

src/librustc_attr/build.rs

@@ -548,7 +548,7 @@ impl Session {
         self.opts.debugging_opts.asm_comments
     }
     pub fn verify_llvm_ir(&self) -> bool {
-        self.opts.debugging_opts.verify_llvm_ir || cfg!(always_verify_llvm_ir)
+        self.opts.debugging_opts.verify_llvm_ir || option_env!("RUSTC_VERIFY_LLVM_IR").is_some()
     }
     pub fn borrowck_stats(&self) -> bool {
         self.opts.debugging_opts.borrowck_stats