Rollup merge of #124480 - Enselic:on-broken-pipe, r=jieyouxu

Change `SIGPIPE` ui from `#[unix_sigpipe = "..."]` to `-Zon-broken-pipe=...`

In the stabilization [attempt](https://github.com/rust-lang/rust/pull/120832) of `#[unix_sigpipe = "sig_dfl"]`, a concern was [raised ](https://github.com/rust-lang/rust/pull/120832#issuecomment-2007394609) related to using a language attribute for the feature: Long term, we want `fn lang_start()` to be definable by any crate, not just libstd. Having a special language attribute in that case becomes awkward.

So as a first step towards the next stabilization attempt, this PR changes the `#[unix_sigpipe = "..."]` attribute to a compiler flag `-Zon-broken-pipe=...` to remove that concern, since now the language is not "contaminated" by this feature.

Another point was [also raised](https://github.com/rust-lang/rust/pull/120832#issuecomment-1987023484), namely that the ui should not leak **how** it does things, but rather what the **end effect** is. The new flag uses the proposed naming. This is of course something that can be iterated on further before stabilization.

Tracking issue: https://github.com/rust-lang/rust/issues/97889

1 files changed, 8 insertions, 0 deletions

diff --git a/compiler/rustc_target/src/spec/mod.rs b/compiler/rustc_target/src/spec/mod.rs
index bd347c1b4b3..cbb248a0fc2 100644
--- a/compiler/rustc_target/src/spec/mod.rs
+++ b/compiler/rustc_target/src/spec/mod.rs
@@ -778,6 +778,14 @@ pub enum PanicStrategy {
     Abort,
 }
 
+#[derive(Clone, Copy, Debug, PartialEq, Hash, Encodable, Decodable, HashStable_Generic)]
+pub enum OnBrokenPipe {
+    Default,
+    Kill,
+    Error,
+    Inherit,
+}
+
 impl PanicStrategy {
     pub fn desc(&self) -> &str {
         match *self {