Rollup merge of #110989 - jyn514:bug-report-url, r=WaffleLapkin

Make the BUG_REPORT_URL configurable by tools

This greatly simplifies how hard it is to set a custom bug report url; previously tools had to copy
the entire hook implementation.

I haven't changed clippy in case they want to make the change upstream instead of the subtree, but
I'm happy to do so here if the maintainers want - cc ````@rust-lang/clippy````

Fixes https://github.com/rust-lang/rust/issues/109486.

src/bin/main.rs

@@ -1,3 +1,5 @@
+#![feature(rustc_private)]
+
 use anyhow::{format_err, Result};
 
 use io::Error as IoError;
@@ -19,7 +21,14 @@
     FormatReportFormatterBuilder, Input, Session, Verbosity,
 };
 
+const BUG_REPORT_URL: &str = "https://github.com/rust-lang/rustfmt/issues/new?labels=bug";
+
+// N.B. these crates are loaded from the sysroot, so they need extern crate.
+extern crate rustc_driver;
+
 fn main() {
+    rustc_driver::install_ice_hook(BUG_REPORT_URL, |_| ());
+
     env_logger::Builder::from_env("RUSTFMT_LOG").init();
     let opts = make_opts();