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

src/librustc_ast/build.rs

@@ -1,5 +0,0 @@
-fn main() {
-    println!("cargo:rerun-if-changed=build.rs");
-    println!("cargo:rerun-if-env-changed=CFG_RELEASE_CHANNEL");
-    println!("cargo:rerun-if-env-changed=CFG_DISABLE_UNSTABLE_FEATURES");
-}

src/librustc_attr/build.rs

@@ -1,5 +0,0 @@
-fn main() {
-    println!("cargo:rerun-if-changed=build.rs");
-    println!("cargo:rerun-if-env-changed=CFG_RELEASE");
-    println!("cargo:rerun-if-env-changed=CFG_RELEASE_CHANNEL");
-}

src/librustc_codegen_llvm/build.rs

@@ -1,6 +0,0 @@
-fn main() {
-    println!("cargo:rerun-if-changed=build.rs");
-    println!("cargo:rerun-if-env-changed=CFG_VERSION");
-    println!("cargo:rerun-if-env-changed=CFG_PREFIX");
-    println!("cargo:rerun-if-env-changed=CFG_LLVM_ROOT");
-}

src/librustc_codegen_ssa/build.rs

@@ -1,4 +0,0 @@
-fn main() {
-    println!("cargo:rerun-if-changed=build.rs");
-    println!("cargo:rerun-if-env-changed=CFG_RELEASE_CHANNEL");
-}

src/librustc_driver/build.rs

@@ -1,7 +0,0 @@
-fn main() {
-    println!("cargo:rerun-if-changed=build.rs");
-    println!("cargo:rerun-if-env-changed=CFG_RELEASE");
-    println!("cargo:rerun-if-env-changed=CFG_VERSION");
-    println!("cargo:rerun-if-env-changed=CFG_VER_DATE");
-    println!("cargo:rerun-if-env-changed=CFG_VER_HASH");
-}

src/librustc_incremental/build.rs

@@ -1,4 +0,0 @@
-fn main() {
-    println!("cargo:rerun-if-changed=build.rs");
-    println!("cargo:rerun-if-env-changed=CFG_VERSION");
-}

src/librustc_interface/build.rs

@@ -1,4 +0,0 @@
-fn main() {
-    println!("cargo:rerun-if-changed=build.rs");
-    println!("cargo:rerun-if-env-changed=RUSTC_INSTALL_BINDIR");
-}

src/librustc_llvm/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_metadata/build.rs

@@ -1,5 +0,0 @@
-fn main() {
-    println!("cargo:rerun-if-changed=build.rs");
-    println!("cargo:rerun-if-env-changed=CFG_VERSION");
-    println!("cargo:rerun-if-env-changed=CFG_VIRTUAL_RUST_SOURCE_BASE_DIR");
-}

src/librustc_middle/build.rs

@@ -1,12 +0,0 @@
-use std::env;
-
-fn main() {
-    println!("cargo:rerun-if-changed=build.rs");
-    println!("cargo:rerun-if-env-changed=CFG_LIBDIR_RELATIVE");
-    println!("cargo:rerun-if-env-changed=CFG_COMPILER_HOST_TRIPLE");
-    println!("cargo:rerun-if-env-changed=RUSTC_VERIFY_LLVM_IR");
-
-    if env::var_os("RUSTC_VERIFY_LLVM_IR").is_some() {
-        println!("cargo:rustc-cfg=always_verify_llvm_ir");
-    }
-}

src/librustc_session/session.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

src/librustc_target/build.rs

@@ -1,4 +0,0 @@
-fn main() {
-    println!("cargo:rerun-if-changed=build.rs");
-    println!("cargo:rerun-if-env-changed=CFG_DEFAULT_LINKER");
-}