Accept verbosity in rustdoc.

Author: o01eg

src/bootstrap/bin/rustdoc.rs

@@ -27,6 +27,13 @@ fn main() {
     let stage = env::var("RUSTC_STAGE").expect("RUSTC_STAGE was not set");
     let sysroot = env::var_os("RUSTC_SYSROOT").expect("RUSTC_SYSROOT was not set");
 
+    use std::str::FromStr;
+
+    let verbose = match env::var("RUSTC_VERBOSE") {
+        Ok(s) => usize::from_str(&s).expect("RUSTC_VERBOSE should be an integer"),
+        Err(_) => 0,
+    };
+
     let mut dylib_path = bootstrap::util::dylib_path();
     dylib_path.insert(0, PathBuf::from(libdir));
 
@@ -63,6 +70,10 @@ fn main() {
         cmd.arg("--deny-render-differences");
     }
 
+    if verbose > 1 {
+        eprintln!("rustdoc command: {:?}", cmd);
+    }
+
     std::process::exit(match cmd.status() {
         Ok(s) => s.code().unwrap_or(1),
         Err(e) => panic!("\n\nfailed to run {:?}: {}\n\n", cmd, e),