diff --git a/configure.ac b/configure.ac
index f5dd1b58..36d358ec 100644
--- a/configure.ac
+++ b/configure.ac
@@ -140,6 +140,23 @@ MY_APPEND_COMPILE_FLAGS([dnl
 -fno-strict-aliasing dnl
 -fno-strict-overflow])
 
+# Emit extra code to check for buffer overflows
+# Could fall back to -fstack-protector when -fstack-protector-strong
+# isnt't supported, for users of older compilers.  Doesn't seem worth
+# the trouble, though.
+# Some ports of the GNU toolchain reportedly support it in the
+# compiler, but not libc.  Use a test program that makes the compiler
+# emit the extra stack checking code, and test it compiles and links.
+AX_APPEND_LINK_FLAGS([-fstack-protector-strong], [], [],
+    [AC_LANG_SOURCE([[
+int
+main(int argc, char *argv[])
+{
+    char arr[64], *dst = arr, *src = argv[0];
+    while ((*dst++ = *src++)) ;
+}
+    ]])])
+
 
 ### Checks for library functions
 
diff --git a/m4/ax_append_flag.m4 b/m4/ax_append_flag.m4
index aeab8997..08f2e07e 100644
--- a/m4/ax_append_flag.m4
+++ b/m4/ax_append_flag.m4
@@ -49,7 +49,7 @@
 #   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
+#serial 6
 
 AC_DEFUN([AX_APPEND_FLAG],
 [dnl
@@ -59,7 +59,7 @@ AS_VAR_SET_IF(FLAGS,[
   AS_CASE([" AS_VAR_GET(FLAGS) "],
     [*" $1 "*], [AC_RUN_LOG([: FLAGS already contains $1])],
     [
-     AS_VAR_APPEND(FLAGS," $1")
+     AS_VAR_APPEND(FLAGS,[" $1"])
      AC_RUN_LOG([: FLAGS="$FLAGS"])
     ])
   ],
diff --git a/m4/ax_append_link_flags.m4 b/m4/ax_append_link_flags.m4
new file mode 100644
index 00000000..fd70fc72
--- /dev/null
+++ b/m4/ax_append_link_flags.m4
@@ -0,0 +1,65 @@
+# ===========================================================================
+#   http://www.gnu.org/software/autoconf-archive/ax_append_link_flags.html
+# ===========================================================================
+#
+# SYNOPSIS
+#
+#   AX_APPEND_LINK_FLAGS([FLAG1 FLAG2 ...], [FLAGS-VARIABLE], [EXTRA-FLAGS], [INPUT])
+#
+# DESCRIPTION
+#
+#   For every FLAG1, FLAG2 it is checked whether the linker works with the
+#   flag.  If it does, the flag is added FLAGS-VARIABLE
+#
+#   If FLAGS-VARIABLE is not specified, the linker's flags (LDFLAGS) is
+#   used. During the check the flag is always added to the linker's flags.
+#
+#   If EXTRA-FLAGS is defined, it is added to the linker's default flags
+#   when the check is done.  The check is thus made with the flags: "LDFLAGS
+#   EXTRA-FLAGS FLAG".  This can for example be used to force the linker to
+#   issue an error when a bad flag is given.
+#
+#   INPUT gives an alternative input source to AC_COMPILE_IFELSE.
+#
+#   NOTE: This macro depends on the AX_APPEND_FLAG and AX_CHECK_LINK_FLAG.
+#   Please keep this macro in sync with AX_APPEND_COMPILE_FLAGS.
+#
+# LICENSE
+#
+#   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 <http://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_APPEND_LINK_FLAGS],
+[AX_REQUIRE_DEFINED([AX_CHECK_LINK_FLAG])
+AX_REQUIRE_DEFINED([AX_APPEND_FLAG])
+for flag in $1; do
+  AX_CHECK_LINK_FLAG([$flag], [AX_APPEND_FLAG([$flag], [m4_default([$2], [LDFLAGS])])], [], [$3], [$4])
+done
+])dnl AX_APPEND_LINK_FLAGS
diff --git a/m4/ax_check_link_flag.m4 b/m4/ax_check_link_flag.m4
new file mode 100644
index 00000000..eb01a6ce
--- /dev/null
+++ b/m4/ax_check_link_flag.m4
@@ -0,0 +1,74 @@
+# ===========================================================================
+#    http://www.gnu.org/software/autoconf-archive/ax_check_link_flag.html
+# ===========================================================================
+#
+# SYNOPSIS
+#
+#   AX_CHECK_LINK_FLAG(FLAG, [ACTION-SUCCESS], [ACTION-FAILURE], [EXTRA-FLAGS], [INPUT])
+#
+# DESCRIPTION
+#
+#   Check whether the given FLAG works with the linker 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 linker's default flags
+#   when the check is done.  The check is thus made with the flags: "LDFLAGS
+#   EXTRA-FLAGS FLAG".  This can for example be used to force the linker to
+#   issue an error when a bad flag is given.
+#
+#   INPUT gives an alternative input source to AC_LINK_IFELSE.
+#
+#   NOTE: Implementation based on AX_CFLAGS_GCC_OPTION. Please keep this
+#   macro in sync with AX_CHECK_{PREPROC,COMPILE}_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 <http://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 4
+
+AC_DEFUN([AX_CHECK_LINK_FLAG],
+[AC_PREREQ(2.64)dnl for _AC_LANG_PREFIX and AS_VAR_IF
+AS_VAR_PUSHDEF([CACHEVAR],[ax_cv_check_ldflags_$4_$1])dnl
+AC_CACHE_CHECK([whether the linker accepts $1], CACHEVAR, [
+  ax_check_save_flags=$LDFLAGS
+  LDFLAGS="$LDFLAGS $4 $1"
+  AC_LINK_IFELSE([m4_default([$5],[AC_LANG_PROGRAM()])],
+    [AS_VAR_SET(CACHEVAR,[yes])],
+    [AS_VAR_SET(CACHEVAR,[no])])
+  LDFLAGS=$ax_check_save_flags])
+AS_VAR_IF(CACHEVAR,yes,
+  [m4_default([$2], :)],
+  [m4_default([$3], :)])
+AS_VAR_POPDEF([CACHEVAR])dnl
+])dnl AX_CHECK_LINK_FLAGS
diff --git a/m4/my_append_compile_flags.m4 b/m4/my_append_compile_flags.m4
index d96fab1d..aa4bf409 100644
--- a/m4/my_append_compile_flags.m4
+++ b/m4/my_append_compile_flags.m4
@@ -1,6 +1,6 @@
 # SYNOPSIS
 #
-#   MY_APPEND_COMPILE_FLAGS([FLAG1 FLAG2 ...], [FLAGS-VARIABLE], [EXTRA-FLAGS])
+#   MY_APPEND_COMPILE_FLAGS([FLAG1 FLAG2 ...], [FLAGS-VARIABLE], [EXTRA-FLAGS], [INPUT])
 #
 # DESCRIPTION
 #
@@ -20,6 +20,8 @@
 #   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: This macro depends on the AX_APPEND_FLAG and
 #   AX_CHECK_COMPILE_FLAG. Please keep this macro in sync with
 #   MY_APPEND_LINK_FLAGS.
@@ -62,6 +64,6 @@ AC_DEFUN([MY_APPEND_COMPILE_FLAGS],
 AX_REQUIRE_DEFINED([AX_APPEND_FLAG])
 for flag in $1; do
   tflag=`echo "$flag" | sed 's/^-Wno-/-W/'`
-  AX_CHECK_COMPILE_FLAG([$tflag], [AX_APPEND_FLAG([$flag], [$2])], [], [$3])
+  AX_CHECK_COMPILE_FLAG([$tflag], [AX_APPEND_FLAG([$flag], [$2])], [], [$3], [$4])
 done
 ])dnl MY_APPEND_COMPILE_FLAGS