C bindings pt3: Type table definitions and barebones files to get generated code to compile.

mojo/public/c/bindings/tests/BUILD.gn

Index: mojo/public/c/bindings/tests/BUILD.gn
diff --git a/mojo/public/c/bindings/tests/BUILD.gn b/mojo/public/c/bindings/tests/BUILD.gn
index 1689e52416c633f3a8ea330d50e8fbbac37cd967..46c2232787f0f704e5ee1f8ce8f2b3fd353150bb 100644
--- a/mojo/public/c/bindings/tests/BUILD.gn
+++ b/mojo/public/c/bindings/tests/BUILD.gn
@@ -20,5 +20,9 @@ mojo_sdk_source_set("tests") {
     "mojo/public/cpp/bindings/tests:mojo_public_bindings_test_utils",
     "mojo/public/cpp/system",
     "mojo/public/c/bindings",
+
+    # The "_c" suffix'd target compiles the generated C bindings to this mojom
+    # target.
+    "mojo/public/interfaces/bindings/tests:test_interfaces_c",
   ]
 }