From c21adbb0b230ffba97cf5d059e2bd024e13a37df Mon Sep 17 00:00:00 2001
From: Khem Raj <raj.khem@gmail.com>
Date: Sat, 22 Apr 2017 11:54:57 -0700
Subject: [PATCH] configure: Check for -Wno-error=format-truncation compiler
 option

If this option is supported by compiler then disable it ( gcc7+)
Fixes
client.c:834:23: error: '%s' directive output may be truncated writing up to 1023 bytes into a region of size 1010 [-Werror=format-truncation=]

Signed-off-by: Khem Raj <raj.khem@gmail.com>

---
 acinclude/ax_check_compile_flag.m4 | 74 ++++++++++++++++++++++++++++++++++++++
 configure.ac                       |  2 ++
 2 files changed, 76 insertions(+)
 create mode 100644 acinclude/ax_check_compile_flag.m4

diff --git a/acinclude/ax_check_compile_flag.m4 b/acinclude/ax_check_compile_flag.m4
new file mode 100644
index 0000000..dcabb92
--- /dev/null
+++ b/acinclude/ax_check_compile_flag.m4
@@ -0,0 +1,74 @@
+# ===========================================================================
+#  https://www.gnu.org/software/autoconf-archive/ax_check_compile_flag.html
+# ===========================================================================
+#
+# SYNOPSIS
+#
+#   AX_CHECK_COMPILE_FLAG(FLAG, [ACTION-SUCCESS], [ACTION-FAILURE], [EXTRA-FLAGS], [INPUT])
+#
+# DESCRIPTION
+#
+#   Check whether the given FLAG works with the current language's compiler
+#   or gives an error.  (Warnings, however, are ignored)
+#
+#   ACTION-SUCCESS/ACTION-FAILURE are shell commands to execute on
+#   success/failure.
+#
+#   If EXTRA-FLAGS is defined, it is added to the current language's default
+#   flags (e.g. CFLAGS) when the check is done.  The check is thus made with
+#   the flags: "CFLAGS EXTRA-FLAGS FLAG".  This can for example be used to
+#   force the compiler to issue an error when a bad flag is given.
+#
+#   INPUT gives an alternative input source to AC_COMPILE_IFELSE.
+#
+#   NOTE: Implementation based on AX_CFLAGS_GCC_OPTION. Please keep this
+#   macro in sync with AX_CHECK_{PREPROC,LINK}_FLAG.
+#
+# LICENSE
+#
+#   Copyright (c) 2008 Guido U. Draheim <guidod@gmx.de>
+#   Copyright (c) 2011 Maarten Bosmans <mkbosmans@gmail.com>
+#
+#   This program is free software: you can redistribute it and/or modify it
+#   under the terms of the GNU General Public License as published by the
+#   Free Software Foundation, either version 3 of the License, or (at your
+#   option) any later version.
+#
+#   This program is distributed in the hope that it will be useful, but
+#   WITHOUT ANY WARRANTY; without even the implied warranty of
+#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
+#   Public License for more details.
+#
+#   You should have received a copy of the GNU General Public License along
+#   with this program. If not, see <https://www.gnu.org/licenses/>.
+#
+#   As a special exception, the respective Autoconf Macro's copyright owner
+#   gives unlimited permission to copy, distribute and modify the configure
+#   scripts that are the output of Autoconf when processing the Macro. You
+#   need not follow the terms of the GNU General Public License when using
+#   or distributing such scripts, even though portions of the text of the
+#   Macro appear in them. The GNU General Public License (GPL) does govern
+#   all other use of the material that constitutes the Autoconf Macro.
+#
+#   This special exception to the GPL applies to versions of the Autoconf
+#   Macro released by the Autoconf Archive. When you make and distribute a
+#   modified version of the Autoconf Macro, you may extend this special
+#   exception to the GPL to apply to your modified version as well.
+
+#serial 5
+
+AC_DEFUN([AX_CHECK_COMPILE_FLAG],
+[AC_PREREQ(2.64)dnl for _AC_LANG_PREFIX and AS_VAR_IF
+AS_VAR_PUSHDEF([CACHEVAR],[ax_cv_check_[]_AC_LANG_ABBREV[]flags_$4_$1])dnl
+AC_CACHE_CHECK([whether _AC_LANG compiler accepts $1], CACHEVAR, [
+  ax_check_save_flags=$[]_AC_LANG_PREFIX[]FLAGS
+  _AC_LANG_PREFIX[]FLAGS="$[]_AC_LANG_PREFIX[]FLAGS $4 $1"
+  AC_COMPILE_IFELSE([m4_default([$5],[AC_LANG_PROGRAM()])],
+    [AS_VAR_SET(CACHEVAR,[yes])],
+    [AS_VAR_SET(CACHEVAR,[no])])
+  _AC_LANG_PREFIX[]FLAGS=$ax_check_save_flags])
+AS_VAR_IF(CACHEVAR,yes,
+  [m4_default([$2], :)],
+  [m4_default([$3], :)])
+AS_VAR_POPDEF([CACHEVAR])dnl
+])dnl AX_CHECK_COMPILE_FLAGS
diff --git a/configure.ac b/configure.ac
index ff4688c..9382fdf 100644
--- a/configure.ac
+++ b/configure.ac
@@ -26,6 +26,7 @@ m4_include([acinclude/pkg.m4])
 m4_include([acinclude/lib-checks.m4])
 m4_include([acinclude/ax_cxx_compile_stdcxx_11.m4])
 m4_include([acinclude/ax_cxx_0x_types.m4])
+m4_include([acinclude/ax_check_compile_flag.m4])
 
 HOSTCXX="$BUILD_CXX"
 PRESET_CFLAGS="$CFLAGS"
@@ -44,6 +45,7 @@ AC_PROG_CXX
 AC_LANG([C++])
 AC_CANONICAL_HOST
 
+AX_CHECK_COMPILE_FLAG([-Werror=format-truncation],[CFLAGS="$CFLAGS -Wno-error=format-truncation" CXXFLAGS="$CXXFLAGS -Wno-error=format-truncation"])
 # Clang 3.2 on some CPUs requires -march-native to detect correctly.
 # GCC 4.3+ can also produce faster executables when its used.
 # But building inside a virtual machine environment has been found to
