Auto merge of #79096 - pietroalbini:stable-build-manifest-newline, r=Mark-Simulacrum

build-manifest: strip newline from rustc version

While running the release process for Rust 1.48.0 I discovered a bug in `build-manifest`: it's not trimming the newline from `src/version`, and it tries to inspect tarballs called `rustc-1.48.0\n-x86_64-unknown-linux-gnu.tar.xz`. The bug only affects stable releases so this is why we're only seeing it right now.

r? `@Mark-Simulacrum`
We'll need to backport this to beta and nightly too.

Author: bors

src/tools/build-manifest/src/versions.rs

@@ -7,7 +7,6 @@ use std::path::{Path, PathBuf};
 use tar::Archive;
 
 const DEFAULT_TARGET: &str = "x86_64-unknown-linux-gnu";
-const RUSTC_VERSION: &str = include_str!("../../../version");
 
 #[derive(Debug, Hash, Eq, PartialEq, Clone)]
 pub(crate) enum PkgType {
@@ -172,10 +171,10 @@ impl Versions {
     ) -> Result<String, Error> {
         let component_name = package.tarball_component_name();
         let version = match self.channel.as_str() {
-            "stable" => RUSTC_VERSION.into(),
+            "stable" => self.rustc_version().into(),
             "beta" => "beta".into(),
             "nightly" => "nightly".into(),
-            _ => format!("{}-dev", RUSTC_VERSION),
+            _ => format!("{}-dev", self.rustc_version()),
         };
 
         if package.target_independent() {
@@ -186,6 +185,7 @@ impl Versions {
     }
 
     pub(crate) fn rustc_version(&self) -> &str {
-        RUSTC_VERSION
+        const RUSTC_VERSION: &str = include_str!("../../../version");
+        RUSTC_VERSION.trim()
     }
 }