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

In the stabilization attempt of `#[unix_sigpipe = "sig_dfl"]`, a concern
was raised 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 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, 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.

1 files changed, 0 insertions, 15 deletions

diff --git a/tests/ui/attributes/unix_sigpipe/unix_sigpipe-rustc_main.rs b/tests/ui/attributes/unix_sigpipe/unix_sigpipe-rustc_main.rs
deleted file mode 100644
index 02a3f48f3b3..00000000000
--- a/tests/ui/attributes/unix_sigpipe/unix_sigpipe-rustc_main.rs
+++ /dev/null
@@ -1,15 +0,0 @@
-//@ run-pass
-//@ aux-build:sigpipe-utils.rs
-
-#![feature(unix_sigpipe)]
-#![feature(rustc_attrs)]
-
-#[unix_sigpipe = "sig_dfl"]
-#[rustc_main]
-fn rustc_main() {
-    extern crate sigpipe_utils;
-
-    // #[unix_sigpipe = "sig_dfl"] is active, so SIGPIPE handler shall be
-    // SIG_DFL. Note that we have a #[rustc_main], but it should still work.
-    sigpipe_utils::assert_sigpipe_handler(sigpipe_utils::SignalHandler::Default);
-}