From c115b39e033979bac7cfd2db5735549430dc14f7 Mon Sep 17 00:00:00 2001
From: nobu <nobu@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
Date: Mon, 3 Sep 2018 08:20:41 +0000
Subject: [PATCH] Declare as gnu_printf on mingw

[Bug #13496]

From: MSP-Greg <MSP-Greg@users.noreply.github.com>

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@64620 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
---
 include/ruby/defines.h              | 5 +++++
 tool/m4/ruby_check_printf_prefix.m4 | 5 +++++
 2 files changed, 10 insertions(+)

diff --git a/include/ruby/defines.h b/include/ruby/defines.h
index 5774870e76..f5fd5bfcef 100644
--- a/include/ruby/defines.h
+++ b/include/ruby/defines.h
@@ -90,8 +90,13 @@ extern "C" {
 #endif /* __GNUC__ >= 3 */
 
 #ifdef __GNUC__
+#ifdef __MINGW32__
+#define PRINTF_ARGS(decl, string_index, first_to_check) \
+  decl __attribute__((format(gnu_printf, string_index, first_to_check)))
+#else
 #define PRINTF_ARGS(decl, string_index, first_to_check) \
   decl __attribute__((format(printf, string_index, first_to_check)))
+#endif
 #else
 #define PRINTF_ARGS(decl, string_index, first_to_check) decl
 #endif
diff --git a/tool/m4/ruby_check_printf_prefix.m4 b/tool/m4/ruby_check_printf_prefix.m4
index 449afef6a7..eab5dbeac6 100644
--- a/tool/m4/ruby_check_printf_prefix.m4
+++ b/tool/m4/ruby_check_printf_prefix.m4
@@ -8,8 +8,13 @@ AC_CACHE_CHECK([for printf prefix for $1], [rb_cv_pri_prefix_]AS_TR_SH($1),[
             [@%:@include <stdio.h>
 	    @%:@include <stddef.h>
             @%:@ifdef __GNUC__
+            @%:@ifdef __MINGW32__
+            @%:@define PRINTF_ARGS(decl, string_index, first_to_check) \
+              decl __attribute__((format(gnu_printf, string_index, first_to_check)))
+            @%:@else
             @%:@define PRINTF_ARGS(decl, string_index, first_to_check) \
               decl __attribute__((format(printf, string_index, first_to_check)))
+            @%:@endif
             @%:@else
             @%:@define PRINTF_ARGS(decl, string_index, first_to_check) decl
             @%:@endif