[clang] [clang] Use ISO C90 style comment in C code (PR #128189)

[via cfe-commits]

https://github.com/foxtran created https://github.com/llvm/llvm-project/pull/128189

This patch fixes warning which occurs during compilation of clang with GCC:
```
C++ style comments are not allowed in ISO C90
```


>From 27640dbf624b062e705b04dc4c55dc61393a7570 Mon Sep 17 00:00:00 2001
From: "Igor S. Gerasimov" <i.s.ger at ya.ru>
Date: Fri, 21 Feb 2025 16:50:14 +0100
Subject: [PATCH] Use ISO C90 style comment in C code

---
 clang/tools/c-index-test/c-index-test.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/clang/tools/c-index-test/c-index-test.c b/clang/tools/c-index-test/c-index-test.c
index 0e7de8b98ea07..2fdb1b2548ff6 100644
--- a/clang/tools/c-index-test/c-index-test.c
+++ b/clang/tools/c-index-test/c-index-test.c
@@ -1223,7 +1223,7 @@ static CXString createCXString(const char *CS) {
 static CXString duplicateCXString(const char *CS) {
   CXString Str;
   Str.data = strdup(CS);
-  Str.private_flags = 1; // CXS_Malloc
+  Str.private_flags = 1; /* CXS_Malloc */
   return Str;
 }