diff --git a/configure.ac b/configure.ac
index 6412330..2178c73 100644
--- a/configure.ac
+++ b/configure.ac
@@ -38,6 +38,7 @@ AC_CONFIG_LIBOBJ_DIR([lib])
 AC_PROG_CC
 AC_PROG_CC_STDC
 AX_CFLAGS_WARN_ALL
+AX_C___ATTRIBUTE__
 
 AC_CONFIG_HEADERS([config.h])
 AC_CONFIG_FILES([
diff --git a/m4/Makefile.am b/m4/Makefile.am
index 7f9cd64..d745318 100644
--- a/m4/Makefile.am
+++ b/m4/Makefile.am
@@ -27,4 +27,6 @@
 # along with this program.  If not, see http://www.gnu.org/licenses/.
 
 
-EXTRA_DIST = ax_cflags_warn_all.m4
+EXTRA_DIST = \
+	ax_c___attribute__.m4 \
+	ax_cflags_warn_all.m4
diff --git a/m4/ax_c___attribute__.m4 b/m4/ax_c___attribute__.m4
new file mode 100644
index 0000000..cf3d62b
--- /dev/null
+++ b/m4/ax_c___attribute__.m4
@@ -0,0 +1,66 @@
+# ===========================================================================
+#    http://www.gnu.org/software/autoconf-archive/ax_c___attribute__.html
+# ===========================================================================
+#
+# SYNOPSIS
+#
+#   AX_C___ATTRIBUTE__
+#
+# DESCRIPTION
+#
+#   Provides a test for the compiler support of __attribute__ extensions.
+#   Defines HAVE___ATTRIBUTE__ if it is found.
+#
+# LICENSE
+#
+#   Copyright (c) 2008 Stepan Kasal <skasal@redhat.com>
+#   Copyright (c) 2008 Christian Haggstrom
+#   Copyright (c) 2008 Ryan McCabe <ryan@numb.org>
+#
+#   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 2 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 8
+
+AC_DEFUN([AX_C___ATTRIBUTE__], [
+  AC_CACHE_CHECK([for __attribute__], [ax_cv___attribute__],
+    [AC_COMPILE_IFELSE(
+      [AC_LANG_PROGRAM(
+	[[#include <stdlib.h>
+	  static void foo(void) __attribute__ ((unused));
+	  static void
+	  foo(void) {
+	      exit(1);
+	  }
+        ]], [])],
+      [ax_cv___attribute__=yes],
+      [ax_cv___attribute__=no]
+    )
+  ])
+  if test "$ax_cv___attribute__" = "yes"; then
+    AC_DEFINE([HAVE___ATTRIBUTE__], 1, [define if your compiler has __attribute__])
+  fi
+])
diff --git a/src/system.h b/src/system.h
index d5d6d4e..28233d1 100644
--- a/src/system.h
+++ b/src/system.h
@@ -73,4 +73,10 @@
 #endif
 
 
+// Compiler __attributes__ for less-capable compilers
+#ifndef HAVE___ATTRIBUTE__
+#  define __attribute__(x)
+#endif
+
+
 #endif /* included_SYSTEM_H */
diff --git a/src/trader.c b/src/trader.c
index 78137db..4e381f8 100644
--- a/src/trader.c
+++ b/src/trader.c
@@ -40,8 +40,8 @@
 
 int main (int argc, char *argv[]);
 static void process_cmdline (int argc, char *argv[]);
-static void show_version (void);
-static void show_usage (int status);
+static void __attribute__((noreturn)) show_version (void);
+static void __attribute__((noreturn)) show_usage (int status);
 
 
 /************************************************************************
@@ -149,7 +149,7 @@ static void process_cmdline (int argc, char *argv[])
   terminates.
 */
 
-static void show_version (void)
+static void __attribute__((noreturn)) show_version (void)
 {
     printf(_("\
 " PACKAGE_NAME " (%s) %s\n\
@@ -178,7 +178,7 @@ NO WARRANTY, to the extent permitted by law; see the License for details.\n\
   error, then terminates.
 */
 
-static void show_usage (int status)
+static void __attribute__((noreturn)) show_usage (int status)
 {
     if (status != EXIT_SUCCESS) {
 	fprintf(stderr, _("%s: Try `%s --help' for more information.\n"),