[emacs][clang-format] Suppress reference to free variable errors (#126254)

vc-git-program is referenced but not defined -- vc-git provides the
definition.

NOKEYCHECK=True
GitOrigin-RevId: d0170424b7250bf5cda0e6253ec62112a6e1c92a
diff --git a/clang-format.el b/clang-format.el
index 54ab2e1..b356e1b 100644
--- a/clang-format.el
+++ b/clang-format.el
@@ -32,6 +32,7 @@
 
 (require 'cl-lib)
 (require 'xml)
+(require 'vc-git)
 
 (defgroup clang-format nil
   "Format code using clang-format."