diff --git a/autoconf/ast_gcc_attribute.m4 b/autoconf/ast_gcc_attribute.m4
index c4488454d974e56d701aef6f5667e093a0cde647..806b39019432dfa24e2353fd8d38882b33994cbf 100644
--- a/autoconf/ast_gcc_attribute.m4
+++ b/autoconf/ast_gcc_attribute.m4
@@ -5,12 +5,12 @@ AC_DEFUN([AST_GCC_ATTRIBUTE],
 [
 AC_MSG_CHECKING(for compiler 'attribute $1' support)
 saved_CFLAGS="$CFLAGS"
-CFLAGS="$CFLAGS -Werror"
+CFLAGS="$CFLAGS -Wall -Wno-unused -Werror"
 
 if test "x$2" = "x"
 then
 AC_COMPILE_IFELSE(
-	AC_LANG_PROGRAM([void __attribute__(($1)) *test(void *muffin, ...) {}],
+	AC_LANG_PROGRAM([static void __attribute__(($1)) *test(void *muffin, ...) {return (void *) 0;}],
 			[]),
 	AC_MSG_RESULT(yes)
 	AC_DEFINE_UNQUOTED([HAVE_ATTRIBUTE_$1], 1, [Define to 1 if your GCC C compiler supports the '$1' attribute.]),
@@ -18,7 +18,7 @@ AC_COMPILE_IFELSE(
 )
 else
 AC_COMPILE_IFELSE(
-	AC_LANG_PROGRAM([void __attribute__(($2)) *test(void *muffin, ...) {}],
+	AC_LANG_PROGRAM([static void __attribute__(($2)) *test(void *muffin, ...) {return (void *) 0;}],
 			[]),
 	AC_MSG_RESULT(yes)
 	AC_DEFINE_UNQUOTED([HAVE_ATTRIBUTE_$1], 1, [Define to 1 if your GCC C compiler supports the '$1' attribute.]),
diff --git a/configure b/configure
index 926cf7f5a0ed97e16895634d276c92423d892525..97015d342c173e4077c9db8c8cfeaf881d3065da 100755
--- a/configure
+++ b/configure
@@ -1,5 +1,5 @@
 #! /bin/sh
-# From configure.ac Revision: 197738 .
+# From configure.ac Revision: 200519 .
 # Guess values for system-dependent variables and create Makefiles.
 # Generated by GNU Autoconf 2.63 for asterisk 1.6.
 #
@@ -18015,7 +18015,7 @@ rm -f core conftest.err conftest.$ac_objext conftest_ipa8_conftest.oo \
 { $as_echo "$as_me:$LINENO: checking for compiler 'attribute pure' support" >&5
 $as_echo_n "checking for compiler 'attribute pure' support... " >&6; }
 saved_CFLAGS="$CFLAGS"
-CFLAGS="$CFLAGS -Werror"
+CFLAGS="$CFLAGS -Wall -Wno-unused -Werror"
 
 if test "x" = "x"
 then
@@ -18025,7 +18025,7 @@ _ACEOF
 cat confdefs.h >>conftest.$ac_ext
 cat >>conftest.$ac_ext <<_ACEOF
 /* end confdefs.h.  */
-void __attribute__((pure)) *test(void *muffin, ...) {}
+static void __attribute__((pure)) *test(void *muffin, ...) {return (void *) 0;}
 int
 main ()
 {
@@ -18076,7 +18076,7 @@ _ACEOF
 cat confdefs.h >>conftest.$ac_ext
 cat >>conftest.$ac_ext <<_ACEOF
 /* end confdefs.h.  */
-void __attribute__(()) *test(void *muffin, ...) {}
+static void __attribute__(()) *test(void *muffin, ...) {return (void *) 0;}
 int
 main ()
 {
@@ -18129,7 +18129,7 @@ CFLAGS="$saved_CFLAGS"
 { $as_echo "$as_me:$LINENO: checking for compiler 'attribute malloc' support" >&5
 $as_echo_n "checking for compiler 'attribute malloc' support... " >&6; }
 saved_CFLAGS="$CFLAGS"
-CFLAGS="$CFLAGS -Werror"
+CFLAGS="$CFLAGS -Wall -Wno-unused -Werror"
 
 if test "x" = "x"
 then
@@ -18139,7 +18139,7 @@ _ACEOF
 cat confdefs.h >>conftest.$ac_ext
 cat >>conftest.$ac_ext <<_ACEOF
 /* end confdefs.h.  */
-void __attribute__((malloc)) *test(void *muffin, ...) {}
+static void __attribute__((malloc)) *test(void *muffin, ...) {return (void *) 0;}
 int
 main ()
 {
@@ -18190,7 +18190,7 @@ _ACEOF
 cat confdefs.h >>conftest.$ac_ext
 cat >>conftest.$ac_ext <<_ACEOF
 /* end confdefs.h.  */
-void __attribute__(()) *test(void *muffin, ...) {}
+static void __attribute__(()) *test(void *muffin, ...) {return (void *) 0;}
 int
 main ()
 {
@@ -18243,7 +18243,7 @@ CFLAGS="$saved_CFLAGS"
 { $as_echo "$as_me:$LINENO: checking for compiler 'attribute const' support" >&5
 $as_echo_n "checking for compiler 'attribute const' support... " >&6; }
 saved_CFLAGS="$CFLAGS"
-CFLAGS="$CFLAGS -Werror"
+CFLAGS="$CFLAGS -Wall -Wno-unused -Werror"
 
 if test "x" = "x"
 then
@@ -18253,7 +18253,7 @@ _ACEOF
 cat confdefs.h >>conftest.$ac_ext
 cat >>conftest.$ac_ext <<_ACEOF
 /* end confdefs.h.  */
-void __attribute__((const)) *test(void *muffin, ...) {}
+static void __attribute__((const)) *test(void *muffin, ...) {return (void *) 0;}
 int
 main ()
 {
@@ -18304,7 +18304,7 @@ _ACEOF
 cat confdefs.h >>conftest.$ac_ext
 cat >>conftest.$ac_ext <<_ACEOF
 /* end confdefs.h.  */
-void __attribute__(()) *test(void *muffin, ...) {}
+static void __attribute__(()) *test(void *muffin, ...) {return (void *) 0;}
 int
 main ()
 {
@@ -18357,7 +18357,7 @@ CFLAGS="$saved_CFLAGS"
 { $as_echo "$as_me:$LINENO: checking for compiler 'attribute unused' support" >&5
 $as_echo_n "checking for compiler 'attribute unused' support... " >&6; }
 saved_CFLAGS="$CFLAGS"
-CFLAGS="$CFLAGS -Werror"
+CFLAGS="$CFLAGS -Wall -Wno-unused -Werror"
 
 if test "x" = "x"
 then
@@ -18367,7 +18367,7 @@ _ACEOF
 cat confdefs.h >>conftest.$ac_ext
 cat >>conftest.$ac_ext <<_ACEOF
 /* end confdefs.h.  */
-void __attribute__((unused)) *test(void *muffin, ...) {}
+static void __attribute__((unused)) *test(void *muffin, ...) {return (void *) 0;}
 int
 main ()
 {
@@ -18418,7 +18418,7 @@ _ACEOF
 cat confdefs.h >>conftest.$ac_ext
 cat >>conftest.$ac_ext <<_ACEOF
 /* end confdefs.h.  */
-void __attribute__(()) *test(void *muffin, ...) {}
+static void __attribute__(()) *test(void *muffin, ...) {return (void *) 0;}
 int
 main ()
 {
@@ -18471,7 +18471,7 @@ CFLAGS="$saved_CFLAGS"
 { $as_echo "$as_me:$LINENO: checking for compiler 'attribute always_inline' support" >&5
 $as_echo_n "checking for compiler 'attribute always_inline' support... " >&6; }
 saved_CFLAGS="$CFLAGS"
-CFLAGS="$CFLAGS -Werror"
+CFLAGS="$CFLAGS -Wall -Wno-unused -Werror"
 
 if test "x" = "x"
 then
@@ -18481,7 +18481,7 @@ _ACEOF
 cat confdefs.h >>conftest.$ac_ext
 cat >>conftest.$ac_ext <<_ACEOF
 /* end confdefs.h.  */
-void __attribute__((always_inline)) *test(void *muffin, ...) {}
+static void __attribute__((always_inline)) *test(void *muffin, ...) {return (void *) 0;}
 int
 main ()
 {
@@ -18532,7 +18532,7 @@ _ACEOF
 cat confdefs.h >>conftest.$ac_ext
 cat >>conftest.$ac_ext <<_ACEOF
 /* end confdefs.h.  */
-void __attribute__(()) *test(void *muffin, ...) {}
+static void __attribute__(()) *test(void *muffin, ...) {return (void *) 0;}
 int
 main ()
 {
@@ -18585,7 +18585,7 @@ CFLAGS="$saved_CFLAGS"
 { $as_echo "$as_me:$LINENO: checking for compiler 'attribute deprecated' support" >&5
 $as_echo_n "checking for compiler 'attribute deprecated' support... " >&6; }
 saved_CFLAGS="$CFLAGS"
-CFLAGS="$CFLAGS -Werror"
+CFLAGS="$CFLAGS -Wall -Wno-unused -Werror"
 
 if test "x" = "x"
 then
@@ -18595,7 +18595,7 @@ _ACEOF
 cat confdefs.h >>conftest.$ac_ext
 cat >>conftest.$ac_ext <<_ACEOF
 /* end confdefs.h.  */
-void __attribute__((deprecated)) *test(void *muffin, ...) {}
+static void __attribute__((deprecated)) *test(void *muffin, ...) {return (void *) 0;}
 int
 main ()
 {
@@ -18646,7 +18646,7 @@ _ACEOF
 cat confdefs.h >>conftest.$ac_ext
 cat >>conftest.$ac_ext <<_ACEOF
 /* end confdefs.h.  */
-void __attribute__(()) *test(void *muffin, ...) {}
+static void __attribute__(()) *test(void *muffin, ...) {return (void *) 0;}
 int
 main ()
 {
@@ -18699,7 +18699,7 @@ CFLAGS="$saved_CFLAGS"
 { $as_echo "$as_me:$LINENO: checking for compiler 'attribute sentinel' support" >&5
 $as_echo_n "checking for compiler 'attribute sentinel' support... " >&6; }
 saved_CFLAGS="$CFLAGS"
-CFLAGS="$CFLAGS -Werror"
+CFLAGS="$CFLAGS -Wall -Wno-unused -Werror"
 
 if test "x" = "x"
 then
@@ -18709,7 +18709,7 @@ _ACEOF
 cat confdefs.h >>conftest.$ac_ext
 cat >>conftest.$ac_ext <<_ACEOF
 /* end confdefs.h.  */
-void __attribute__((sentinel)) *test(void *muffin, ...) {}
+static void __attribute__((sentinel)) *test(void *muffin, ...) {return (void *) 0;}
 int
 main ()
 {
@@ -18760,7 +18760,7 @@ _ACEOF
 cat confdefs.h >>conftest.$ac_ext
 cat >>conftest.$ac_ext <<_ACEOF
 /* end confdefs.h.  */
-void __attribute__(()) *test(void *muffin, ...) {}
+static void __attribute__(()) *test(void *muffin, ...) {return (void *) 0;}
 int
 main ()
 {
@@ -18813,7 +18813,7 @@ CFLAGS="$saved_CFLAGS"
 { $as_echo "$as_me:$LINENO: checking for compiler 'attribute warn_unused_result' support" >&5
 $as_echo_n "checking for compiler 'attribute warn_unused_result' support... " >&6; }
 saved_CFLAGS="$CFLAGS"
-CFLAGS="$CFLAGS -Werror"
+CFLAGS="$CFLAGS -Wall -Wno-unused -Werror"
 
 if test "x" = "x"
 then
@@ -18823,7 +18823,7 @@ _ACEOF
 cat confdefs.h >>conftest.$ac_ext
 cat >>conftest.$ac_ext <<_ACEOF
 /* end confdefs.h.  */
-void __attribute__((warn_unused_result)) *test(void *muffin, ...) {}
+static void __attribute__((warn_unused_result)) *test(void *muffin, ...) {return (void *) 0;}
 int
 main ()
 {
@@ -18874,7 +18874,7 @@ _ACEOF
 cat confdefs.h >>conftest.$ac_ext
 cat >>conftest.$ac_ext <<_ACEOF
 /* end confdefs.h.  */
-void __attribute__(()) *test(void *muffin, ...) {}
+static void __attribute__(()) *test(void *muffin, ...) {return (void *) 0;}
 int
 main ()
 {
@@ -18927,7 +18927,7 @@ CFLAGS="$saved_CFLAGS"
 { $as_echo "$as_me:$LINENO: checking for compiler 'attribute weakref' support" >&5
 $as_echo_n "checking for compiler 'attribute weakref' support... " >&6; }
 saved_CFLAGS="$CFLAGS"
-CFLAGS="$CFLAGS -Werror"
+CFLAGS="$CFLAGS -Wall -Wno-unused -Werror"
 
 if test "xweakref("foo")" = "x"
 then
@@ -18937,7 +18937,7 @@ _ACEOF
 cat confdefs.h >>conftest.$ac_ext
 cat >>conftest.$ac_ext <<_ACEOF
 /* end confdefs.h.  */
-void __attribute__((weakref)) *test(void *muffin, ...) {}
+static void __attribute__((weakref)) *test(void *muffin, ...) {return (void *) 0;}
 int
 main ()
 {
@@ -18988,7 +18988,7 @@ _ACEOF
 cat confdefs.h >>conftest.$ac_ext
 cat >>conftest.$ac_ext <<_ACEOF
 /* end confdefs.h.  */
-void __attribute__((weakref("foo"))) *test(void *muffin, ...) {}
+static void __attribute__((weakref("foo"))) *test(void *muffin, ...) {return (void *) 0;}
 int
 main ()
 {
@@ -19041,7 +19041,7 @@ CFLAGS="$saved_CFLAGS"
 { $as_echo "$as_me:$LINENO: checking for compiler 'attribute weak_import' support" >&5
 $as_echo_n "checking for compiler 'attribute weak_import' support... " >&6; }
 saved_CFLAGS="$CFLAGS"
-CFLAGS="$CFLAGS -Werror"
+CFLAGS="$CFLAGS -Wall -Wno-unused -Werror"
 
 if test "x" = "x"
 then
@@ -19051,7 +19051,7 @@ _ACEOF
 cat confdefs.h >>conftest.$ac_ext
 cat >>conftest.$ac_ext <<_ACEOF
 /* end confdefs.h.  */
-void __attribute__((weak_import)) *test(void *muffin, ...) {}
+static void __attribute__((weak_import)) *test(void *muffin, ...) {return (void *) 0;}
 int
 main ()
 {
@@ -19102,7 +19102,7 @@ _ACEOF
 cat confdefs.h >>conftest.$ac_ext
 cat >>conftest.$ac_ext <<_ACEOF
 /* end confdefs.h.  */
-void __attribute__(()) *test(void *muffin, ...) {}
+static void __attribute__(()) *test(void *muffin, ...) {return (void *) 0;}
 int
 main ()
 {