unix_sigpipe: Add unix_sigpipe-different-duplicates.rs test variant

And use the "sig_dfl" variant as much as possible since that is the
"least wrong" of all the variants, especially considering that it will
be the first variant to be stabilized.

Author: Enselic

tests/ui/attributes/unix_sigpipe/unix_sigpipe-different-duplicates.rs

@@ -0,0 +1,5 @@
+#![feature(unix_sigpipe)]
+
+#[unix_sigpipe = "sig_dfl"]
+#[unix_sigpipe = "sig_ign"] //~ error: multiple `unix_sigpipe` attributes
+fn main() {}

tests/ui/attributes/unix_sigpipe/unix_sigpipe-different-duplicates.stderr

@@ -0,0 +1,14 @@
+error: multiple `unix_sigpipe` attributes
+  --> $DIR/unix_sigpipe-different-duplicates.rs:4:1
+   |
+LL | #[unix_sigpipe = "sig_ign"]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: remove this attribute
+   |
+note: attribute also specified here
+  --> $DIR/unix_sigpipe-different-duplicates.rs:3:1
+   |
+LL | #[unix_sigpipe = "sig_dfl"]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to 1 previous error
+

tests/ui/attributes/unix_sigpipe/unix_sigpipe-duplicates.rs

@@ -1,5 +1,5 @@
 #![feature(unix_sigpipe)]
 
-#[unix_sigpipe = "sig_ign"]
-#[unix_sigpipe = "inherit"] //~ error: multiple `unix_sigpipe` attributes
+#[unix_sigpipe = "sig_dfl"]
+#[unix_sigpipe = "sig_dfl"] //~ error: multiple `unix_sigpipe` attributes
 fn main() {}

tests/ui/attributes/unix_sigpipe/unix_sigpipe-duplicates.stderr

@@ -1,13 +1,13 @@
 error: multiple `unix_sigpipe` attributes
   --> $DIR/unix_sigpipe-duplicates.rs:4:1
    |
-LL | #[unix_sigpipe = "inherit"]
+LL | #[unix_sigpipe = "sig_dfl"]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: remove this attribute
    |
 note: attribute also specified here
   --> $DIR/unix_sigpipe-duplicates.rs:3:1
    |
-LL | #[unix_sigpipe = "sig_ign"]
+LL | #[unix_sigpipe = "sig_dfl"]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: aborting due to 1 previous error