[libc] Add VISIT enum for search.h (#132746)

This patch introduces the `VISIT` enum for tree search. Existing tests
ensure the correct generation of headers.

libc/include/CMakeLists.txt

@@ -245,6 +245,7 @@ add_header_macro(
     .llvm-libc-types.ENTRY
     .llvm-libc-types.struct_hsearch_data
     .llvm-libc-types.size_t
+    .llvm-libc-types.VISIT
     .llvm-libc-types.__lsearchcompare_t
 )
 

libc/include/llvm-libc-types/CMakeLists.txt

@@ -128,6 +128,7 @@ add_header(struct_iovec HDR struct_iovec.h DEPENDS .size_t)
 add_header(struct_msghdr HDR struct_msghdr.h DEPENDS .size_t .socklen_t .struct_iovec)
 add_header(ACTION HDR ACTION.h)
 add_header(ENTRY HDR ENTRY.h)
+add_header(VISIT HDR VISIT.h)
 add_header(struct_hsearch_data HDR struct_hsearch_data.h)
 add_header(struct_epoll_event HDR struct_epoll_event.h)
 add_header(struct_epoll_data HDR struct_epoll_data.h)

libc/include/llvm-libc-types/VISIT.h

@@ -0,0 +1,14 @@
+//===-- Definition of VISIT type ------------------------------------------===//
+//
+// 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_TYPES_VISIT_H
+#define LLVM_LIBC_TYPES_VISIT_H
+
+typedef enum { preorder, postorder, endorder, leaf } VISIT;
+
+#endif // LLVM_LIBC_TYPES_VISIT_H

libc/include/search.yaml

@@ -5,6 +5,7 @@ types:
   - type_name: struct_hsearch_data
   - type_name: ENTRY
   - type_name: ACTION
+  - type_name: VISIT
   - type_name: __lsearchcompare_t
 enums: []
 objects: []