rust: Alias rust_ffi_rlib to rust_library_rlib

With the new transition mutators, the distinctions between rust_ffi_rlib
and rust_library_rlib are not necessary. This CL removes the remaining
distinctions to allow an unusual use case where a rust_library and a
rust_ffi_rlib would otherwise be created from the same source. This
would allow defining a single rust_library_rlib that works for both rust
modules and cc modules.

One key change is that rust_ffi_rlibs only produced an rlib-std variant
previously, and now produce dylib-std variants as well.This surfaced an
issue where a libstd linkage mismatch would cause rustc to throw a
consufing missing crate error. We instead add logic to catch this in
Soong and provide a more useful error message.

Bug: 383552450
Test: m rust
Test: m blueprint_tests
Change-Id: I611ca46934059735d06229952cfd8e0ab7050486
diff --git a/rust/rust_test.go b/rust/rust_test.go
index 767508d..7e64c0a 100644
--- a/rust/rust_test.go
+++ b/rust/rust_test.go
@@ -547,3 +547,31 @@
 		t.Errorf("expected %q got %q", expected, got)
 	}
 }
+
+func TestStdLinkMismatch(t *testing.T) {
+	// Test that we catch cases where the std linkage mismatches. This leads to
+	// a confusing rustc error where a crate is declared missing despite being
+	// passed in as a rustlib dependency / via the --extern flag. Thus, we want
+	// to make sure we detect it in Soong.
+
+	// libfoo depends on libbar as an rlib, but does not link libstd as an rlib.
+	// libbar only links libstd as an rlib (prefer_rlib).
+	testRustError(t, "wrong StdLinkage", `
+		rust_library {
+			name: "libfoo",
+			crate_name: "foo",
+			srcs: [
+				"foo.rs",
+			],
+			rlibs: ["libbar"],
+		}
+		rust_library {
+			name: "libbar",
+			crate_name: "bar",
+			srcs: [
+				"bar.rs",
+			],
+			prefer_rlib: true,
+		}
+	`)
+}