Remove unneeded special case for rust CI

Author: GuillaumeGomez

compiler/rustc_codegen_gcc/build_system/src/config.rs

@@ -377,39 +377,18 @@ impl ConfigInfo {
             "debug"
         };
 
-        let has_builtin_backend = env
-            .get("BUILTIN_BACKEND")
-            .map(|backend| !backend.is_empty())
-            .unwrap_or(false);
-
         let mut rustflags = Vec::new();
-        if has_builtin_backend {
-            // It means we're building inside the rustc testsuite, so some options need to be handled
-            // a bit differently.
-            self.cg_backend_path = "gcc".to_string();
-
-            match env.get("RUSTC_SYSROOT") {
-                Some(rustc_sysroot) if !rustc_sysroot.is_empty() => {
-                    rustflags.extend_from_slice(&["--sysroot".to_string(), rustc_sysroot.clone()]);
-                }
-                _ => {}
-            }
-            // This should not be needed, but is necessary for the CI in the rust repository.
-            // FIXME: Remove when the rust CI switches to the master version of libgccjit.
-            rustflags.push("-Cpanic=abort".to_string());
-        } else {
-            self.cg_backend_path = current_dir
-                .join("target")
-                .join(channel)
-                .join(&format!("librustc_codegen_gcc.{}", self.dylib_ext))
-                .display()
-                .to_string();
-            self.sysroot_path = current_dir
-                .join("build_sysroot/sysroot")
-                .display()
-                .to_string();
-            rustflags.extend_from_slice(&["--sysroot".to_string(), self.sysroot_path.clone()]);
-        };
+        self.cg_backend_path = current_dir
+            .join("target")
+            .join(channel)
+            .join(&format!("librustc_codegen_gcc.{}", self.dylib_ext))
+            .display()
+            .to_string();
+        // self.sysroot_path = current_dir
+        //     .join("build_sysroot/sysroot")
+        //     .display()
+        //     .to_string();
+        // rustflags.extend_from_slice(&["--sysroot".to_string(), self.sysroot_path.clone()]);
 
         // This environment variable is useful in case we want to change options of rustc commands.
         if let Some(cg_rustflags) = env.get("CG_RUSTFLAGS") {