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, 12 deletions

diff --git a/tests/ui/attributes/unix_sigpipe/unix_sigpipe-not-used.rs b/tests/ui/attributes/unix_sigpipe/unix_sigpipe-not-used.rs
deleted file mode 100644
index b0044f5e919..00000000000
--- a/tests/ui/attributes/unix_sigpipe/unix_sigpipe-not-used.rs
+++ /dev/null
@@ -1,12 +0,0 @@
-//@ revisions: with_feature without_feature
-//@ run-pass
-//@ aux-build:sigpipe-utils.rs
-
-#![cfg_attr(with_feature, feature(unix_sigpipe))]
-
-fn main() {
-    extern crate sigpipe_utils;
-
-    // SIGPIPE shall be ignored since #[unix_sigpipe = "..."] is not used
-    sigpipe_utils::assert_sigpipe_handler(sigpipe_utils::SignalHandler::Ignore);
-}