From 439990318d90a689b2ac067b41c3462ddda60ae5 Mon Sep 17 00:00:00 2001
From: Lars Kanis <kanis@comcard.de>
Date: Fri, 18 Nov 2022 19:30:14 +0100
Subject: [PATCH] Avoid warnings on MINGW:

win32/win32.c: In function 'rtc_error_handler':
win32/win32.c:691:5: warning: function 'rtc_error_handler' might be a candidate for 'gnu_printf' format attribute [-Wsuggest-attribute=format]
  691 |     rb_str_vcatf(str, fmt, ap);
      |     ^~~~~~~~~~~~

and

win32/win32.c:683:1: warning: 'rtc_error_handler' defined but not used [-Wunused-function]
  683 | rtc_error_handler(int e, const char *src, int line, const char *exe, const char *fmt, ...)
      | ^~~~~~~~~~~~~~~~~
---
 win32/win32.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/win32/win32.c b/win32/win32.c
index fee31677f0..b9af42d9c9 100644
--- a/win32/win32.c
+++ b/win32/win32.c
@@ -681,7 +681,10 @@ invalid_parameter(const wchar_t *expr, const wchar_t *func, const wchar_t *file,
 
 int ruby_w32_rtc_error;
 
+# ifndef __MINGW32__
 /* License: Ruby's */
+RBIMPL_ATTR_NONNULL((5))
+RBIMPL_ATTR_FORMAT(RBIMPL_PRINTF_FORMAT, 5, 6)
 static int __cdecl
 rtc_error_handler(int e, const char *src, int line, const char *exe, const char *fmt, ...)
 {
@@ -697,6 +700,7 @@ rtc_error_handler(int e, const char *src, int line, const char *exe, const char
     rb_write_error2(RSTRING_PTR(str), RSTRING_LEN(str));
     return 0;
 }
+# endif
 #endif
 
 static CRITICAL_SECTION select_mutex;