From 2dada9e472ad2b35513ab0d5f1cbac4bfa5363f7 Mon Sep 17 00:00:00 2001
From: Viktor Szakats <commit@vsz.me>
Date: Thu, 24 Jul 2025 16:01:45 +0200
Subject: [PATCH] build: include wincrypt.h for if_nametoindex detection

---
 CMakeLists.txt | 3 ++-
 configure.ac   | 1 +
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 334b5c3865..10d171bcc9 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1785,7 +1785,8 @@ check_function_exists("setlocale"       HAVE_SETLOCALE)
 check_function_exists("setrlimit"       HAVE_SETRLIMIT)
 
 if(WIN32)
-  check_symbol_exists("if_nametoindex"  "winsock2.h;iphlpapi.h" HAVE_IF_NAMETOINDEX)  # Windows Vista+ non-UWP
+  # include wincrypt.h for mingw-w64 __MINGW64_VERSION_MAJOR <= 5 */
+  check_symbol_exists("if_nametoindex"  "winsock2.h;wincrypt.h;iphlpapi.h" HAVE_IF_NAMETOINDEX)  # Windows Vista+ non-UWP */
 else()
   check_function_exists("if_nametoindex"  HAVE_IF_NAMETOINDEX)  # net/if.h
   check_function_exists("realpath"        HAVE_REALPATH)
diff --git a/configure.ac b/configure.ac
index acf253eadc..2fafff1fdf 100644
--- a/configure.ac
+++ b/configure.ac
@@ -4275,6 +4275,7 @@ if test "$curl_cv_native_windows" = 'yes'; then
       #define WIN32_LEAN_AND_MEAN
       #endif
       #include <winsock2.h>
+      #include <wincrypt.h>  /* for mingw-w64 __MINGW64_VERSION_MAJOR <= 5 */
       #include <iphlpapi.h>
     ]],[[
       if_nametoindex("");