std: make compilation of libpanic_unwind optional via a Cargo feature

with this feature disabled, you can (Cargo) compile std with
"panic=abort"

rustbuild will build std with this feature enabled, to maintain the
status quo

fixes #37252

1 files changed, 1 insertions, 1 deletions

diff --git a/src/bootstrap/lib.rs b/src/bootstrap/lib.rs
index 828e82d3832..b751031e88b 100644
--- a/src/bootstrap/lib.rs
+++ b/src/bootstrap/lib.rs
@@ -507,7 +507,7 @@ impl Build {
     /// Get the space-separated set of activated features for the standard
     /// library.
     fn std_features(&self) -> String {
-        let mut features = String::new();
+        let mut features = "panic-unwind".to_string();
         if self.config.debug_jemalloc {
             features.push_str(" debug-jemalloc");
         }