From c41f233c4c38e84023a16339782ee306f03e7f59 Mon Sep 17 00:00:00 2001
From: Paul Eggert <address@hidden>
Date: Fri, 7 Jul 2017 14:10:20 -0700
Subject: [PATCH] vasnprintf: port to macOS 10.13
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Problem reported by comex in:
http://lists.gnu.org/archive/html/bug-gnulib/2017-07/msg00056.html
* lib/vasnprintf.c (VASNPRINTF): Don’t use %n on macOS.
---
 ChangeLog        | 7 +++++++
 lib/vasnprintf.c | 9 ++++++++-
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/ChangeLog b/ChangeLog
index 14fa6fa..176abb9 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2017-07-07  Paul Eggert  <address@hidden>
+
+	vasnprintf: port to macOS 10.13
+	Problem reported by comex in:
+	http://lists.gnu.org/archive/html/bug-gnulib/2017-07/msg00056.html
+	* lib/vasnprintf.c (VASNPRINTF): Don’t use %n on macOS.
+
 2017-07-06  Bruno Haible  <address@hidden>
 
 	imaxdiv tests: Fix logic.
diff --git a/lib/vasnprintf.c b/lib/vasnprintf.c
index 9c2af0e..fecaf27 100644
--- a/lib/vasnprintf.c
+++ b/lib/vasnprintf.c
@@ -4869,7 +4869,11 @@ VASNPRINTF (DCHAR_T *resultbuf, size_t *lengthp,
 #endif
                   *fbp = dp->conversion;
 #if USE_SNPRINTF
-# if !(((__GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 3)) && !defined __UCLIBC__) || ((defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__))
+# if ! (((__GLIBC__ > 2                                                 \
+          || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 3))                  \
+         && !defined __UCLIBC__)                                        \
+        || (defined __APPLE__ && defined __MACH__)                      \
+        || ((defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__))
                 fbp[1] = '%';
                 fbp[2] = 'n';
                 fbp[3] = '\0';
@@ -4883,6 +4887,9 @@ VASNPRINTF (DCHAR_T *resultbuf, size_t *lengthp,
                    in format strings in writable memory may crash the program
                    (if compiled with _FORTIFY_SOURCE=2), so we should avoid it
                    in this situation.  */
+                /* macOS 10.13 High Sierra behaves like glibc with
+                   _FORTIFY_SOURCE=2, and older macOS releases
+                   presumably do not need %n.  */
                 /* On native Windows systems (such as mingw), we can avoid using
                    %n because:
                      - Although the gl_SNPRINTF_TRUNCATION_C99 test fails,
-- 
2.7.4