Add git diff headers to Opus Bazel patch

Co-authored-by: Codex <noreply@openai.com>

patches/opus_windows_gnullvm_stack_probe.patch

@@ -1,3 +1,4 @@
+diff --git a/BUILD.bazel b/BUILD.bazel
 --- a/BUILD.bazel
 +++ b/BUILD.bazel
 @@ -1,5 +1,5 @@
@@ -113,6 +114,7 @@
      includes = ["include"],
      deps = [
          ":celt",
+diff --git a/defs.bzl b/defs.bzl
 --- a/defs.bzl
 +++ b/defs.bzl
 @@ -1,4 +1,9 @@