weakref attribute detection broken with gcc 4.6 and higher

GCC 4.7 Manual:
http://gcc.gnu.org/onlinedocs/gcc-4.7.4/gcc/Function-Attributes.html

weakref ("target")

A weak reference is an alias that does not by itself require a definition
to be given for the target symbol.

ASTERISK-22559 #close
Reported by: Ibercom

Change-Id: I36a136cae947b65187a697533416f9ff9a0b8cdf

autoconf/ast_gcc_attribute.m4

@@ -20,7 +20,7 @@ AC_COMPILE_IFELSE(
 )
 else
 AC_COMPILE_IFELSE(
-	[AC_LANG_PROGRAM([$3 void __attribute__(($2)) *test(void *muffin, ...) {return (void *) 0;}],
+	[AC_LANG_PROGRAM([$3 void __attribute__(($2)) *test(void *muffin, ...) ;],
 			[])],
 	AC_MSG_RESULT(yes)
 	m4_ifval([$4],$4=1)

configure

@@ -16666,7 +16666,7 @@ rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
 else
 cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
- void __attribute__(()) *test(void *muffin, ...) {return (void *) 0;}
+ void __attribute__(()) *test(void *muffin, ...) ;
 int
 main ()
 {
@@ -16734,7 +16734,7 @@ rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
 else
 cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
- void __attribute__(()) *test(void *muffin, ...) {return (void *) 0;}
+ void __attribute__(()) *test(void *muffin, ...) ;
 int
 main ()
 {
@@ -16802,7 +16802,7 @@ rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
 else
 cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
- void __attribute__(()) *test(void *muffin, ...) {return (void *) 0;}
+ void __attribute__(()) *test(void *muffin, ...) ;
 int
 main ()
 {
@@ -16870,7 +16870,7 @@ rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
 else
 cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
- void __attribute__(()) *test(void *muffin, ...) {return (void *) 0;}
+ void __attribute__(()) *test(void *muffin, ...) ;
 int
 main ()
 {
@@ -16938,7 +16938,7 @@ rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
 else
 cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
- void __attribute__(()) *test(void *muffin, ...) {return (void *) 0;}
+ void __attribute__(()) *test(void *muffin, ...) ;
 int
 main ()
 {
@@ -17006,7 +17006,7 @@ rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
 else
 cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
- void __attribute__(()) *test(void *muffin, ...) {return (void *) 0;}
+ void __attribute__(()) *test(void *muffin, ...) ;
 int
 main ()
 {
@@ -17074,7 +17074,7 @@ rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
 else
 cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
- void __attribute__(()) *test(void *muffin, ...) {return (void *) 0;}
+ void __attribute__(()) *test(void *muffin, ...) ;
 int
 main ()
 {
@@ -17142,7 +17142,7 @@ rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
 else
 cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
- void __attribute__(()) *test(void *muffin, ...) {return (void *) 0;}
+ void __attribute__(()) *test(void *muffin, ...) ;
 int
 main ()
 {
@@ -17210,7 +17210,7 @@ rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
 else
 cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
- void __attribute__(()) *test(void *muffin, ...) {return (void *) 0;}
+ void __attribute__(()) *test(void *muffin, ...) ;
 int
 main ()
 {
@@ -17278,7 +17278,7 @@ rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
 else
 cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
- void __attribute__(()) *test(void *muffin, ...) {return (void *) 0;}
+ void __attribute__(()) *test(void *muffin, ...) ;
 int
 main ()
 {
@@ -17346,7 +17346,7 @@ rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
 else
 cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
- void __attribute__(()) *test(void *muffin, ...) {return (void *) 0;}
+ void __attribute__(()) *test(void *muffin, ...) ;
 int
 main ()
 {

menuselect/configure

@@ -3227,7 +3227,7 @@ rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
 else
 cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
- void __attribute__(()) *test(void *muffin, ...) {return (void *) 0;}
+ void __attribute__(()) *test(void *muffin, ...) ;
 int
 main ()
 {
@@ -3299,7 +3299,7 @@ rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
 else
 cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
- void __attribute__(()) *test(void *muffin, ...) {return (void *) 0;}
+ void __attribute__(()) *test(void *muffin, ...) ;
 int
 main ()
 {
@@ -3371,7 +3371,7 @@ rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
 else
 cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
-static void __attribute__((weakref("foo"))) *test(void *muffin, ...) {return (void *) 0;}
+static void __attribute__((weakref("foo"))) *test(void *muffin, ...) ;
 int
 main ()
 {
@@ -3445,7 +3445,7 @@ rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
 else
 cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
-static void __attribute__((weakref("foo"))) *test(void *muffin, ...) {return (void *) 0;}
+static void __attribute__((weakref("foo"))) *test(void *muffin, ...) ;
 int
 main ()
 {