add the same test as commit:764bfdcb9f for __gnu_cxx::__exchange_and_add

refs #8

Author: nobu-k

configure.in

@@ -65,7 +65,7 @@ add CFLAGS="-march=i686" and CXXFLAGS="-march=i686" options to ./configure as fo
 			#include <bits/atomicity.h>
 			int atomic_sub(int i) { return __gnu_cxx::__exchange_and_add(&i, -1) - 1; }
 			int atomic_add(int i) { return __gnu_cxx::__exchange_and_add(&i, 1) + 1; }
-		], [], msgpack_cv_gcc_cxx_atomic_ops="yes")
+		], [atomic_sub(1); atomic_add(1);], msgpack_cv_gcc_cxx_atomic_ops="yes")
 		])
 	AC_LANG_POP([C++])