[libc][obvious] Add license headers to APIIndexer.[cpp|h].

GitOrigin-RevId: cd7a5c3cd9a4891654b1b36f743a250135eb5c5a
diff --git a/utils/LibcTableGenUtil/APIIndexer.cpp b/utils/LibcTableGenUtil/APIIndexer.cpp
index 934d713..366dea9 100644
--- a/utils/LibcTableGenUtil/APIIndexer.cpp
+++ b/utils/LibcTableGenUtil/APIIndexer.cpp
@@ -1,3 +1,10 @@
+//===-- Implementation of APIIndexer clas ---------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
 
 #include "APIIndexer.h"
 
diff --git a/utils/LibcTableGenUtil/APIIndexer.h b/utils/LibcTableGenUtil/APIIndexer.h
index a0f0acf..8fa8711 100644
--- a/utils/LibcTableGenUtil/APIIndexer.h
+++ b/utils/LibcTableGenUtil/APIIndexer.h
@@ -1,3 +1,13 @@
+//===-- A class to index libc API listed in tablegen files ------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_UTILS_LIBC_TABLE_GEN_UTILS_API_INDEXER_H
+#define LLVM_LIBC_UTILS_LIBC_TABLE_GEN_UTILS_API_INDEXER_H
 
 #include "llvm/ADT/StringRef.h"
 #include "llvm/TableGen/Record.h"
@@ -64,3 +74,5 @@
 };
 
 } // namespace llvm_libc
+
+#endif // LLVM_LIBC_UTILS_LIBC_TABLE_GEN_UTILS_API_INDEXER_H