Auto merge of #115471 - RalfJung:skipping-sanity, r=onur-ozkan

also skip musl checks when BOOTSTRAP_SKIP_TARGET_SANITY is set

Currently I cannot test musl targets in Miri via x.py; this PR fixes that.

src/bootstrap/sanity.rs

@@ -62,6 +62,9 @@ impl Finder {
 }
 
 pub fn check(build: &mut Build) {
+    let skip_target_sanity =
+        env::var_os("BOOTSTRAP_SKIP_TARGET_SANITY").is_some_and(|s| s == "1" || s == "true");
+
     let path = env::var_os("PATH").unwrap_or_default();
     // On Windows, quotes are invalid characters for filename paths, and if
     // one is present as part of the PATH then that can lead to the system
@@ -166,7 +169,7 @@ than building it.
         // FIXME: it would be better to refactor this code to split necessary setup from pure sanity
         // checks, and have a regular flag for skipping the latter. Also see
         // <https://github.com/rust-lang/rust/pull/103569#discussion_r1008741742>.
-        if env::var_os("BOOTSTRAP_SKIP_TARGET_SANITY").is_some() {
+        if skip_target_sanity {
             continue;
         }
 
@@ -205,7 +208,15 @@ than building it.
             }
         }
 
-        // Make sure musl-root is valid
+        // Some environments don't want or need these tools, such as when testing Miri.
+        // FIXME: it would be better to refactor this code to split necessary setup from pure sanity
+        // checks, and have a regular flag for skipping the latter. Also see
+        // <https://github.com/rust-lang/rust/pull/103569#discussion_r1008741742>.
+        if skip_target_sanity {
+            continue;
+        }
+
+        // Make sure musl-root is valid.
         if target.contains("musl") && !target.contains("unikraft") {
             // If this is a native target (host is also musl) and no musl-root is given,
             // fall back to the system toolchain in /usr before giving up
@@ -227,14 +238,6 @@ than building it.
             }
         }
 
-        // Some environments don't want or need these tools, such as when testing Miri.
-        // FIXME: it would be better to refactor this code to split necessary setup from pure sanity
-        // checks, and have a regular flag for skipping the latter. Also see
-        // <https://github.com/rust-lang/rust/pull/103569#discussion_r1008741742>.
-        if env::var_os("BOOTSTRAP_SKIP_TARGET_SANITY").is_some() {
-            continue;
-        }
-
         if need_cmake && target.contains("msvc") {
             // There are three builds of cmake on windows: MSVC, MinGW, and
             // Cygwin. The Cygwin build does not have generators for Visual