Add -Zcross-crate-inline-threshold=yes

tests/codegen/cross-crate-inlining/always-inline.rs

@@ -0,0 +1,13 @@
+// compile-flags: -O
+// aux-build:always.rs
+
+#![crate_type = "lib"]
+
+extern crate always;
+
+// Check that we inline a cross-crate call, even though it isn't a leaf
+#[no_mangle]
+pub fn outer() -> String {
+    // CHECK-NOT: call {{.*}}stem_fn
+    always::stem_fn()
+}