add missing file make_shared.m4

[[Imported from SVN: r6353]]

m4/make_shared.m4

+AC_DEFUN([BOOST_MAKE_SHARED_HPP],[
+  AC_REQUIRE([AC_PROG_CXX])
+  AC_LANG_PUSH([C++])
+     AC_CHECK_HEADER([boost/make_shared.hpp],
+                     [AC_DEFINE([HAVE_BOOST_MAKE_SHARED_HPP], [1],
+                        [Define to 1 if you have <boost/make_shared.hpp>.])])
+  AC_LANG_POP
+])