configure.in: HAVE_ATTRIBUTE_FUNCTION_ALIAS

* configure.in (HAVE_ATTRIBUTE_FUNCTION_ALIAS): define to tell if
  alias attribute is available.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@40998 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,8 @@
+Fri May 31 16:35:44 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* configure.in (HAVE_ATTRIBUTE_FUNCTION_ALIAS): define to tell if
+	  alias attribute is available.
+
 Fri May 31 16:03:23 2013  Zachary Scott  <zachary@zacharyscott.net>
 
 	* object.c, proc.c: s/call_seq/call-seq in rdoc. [Fix GH-322]

configure.in

@@ -1392,6 +1392,7 @@ if test "$GCC" = yes; then
 		[rb_cv_gcc_function_alias=$a; break])
 	done])
     if test "$rb_cv_gcc_function_alias" != no; then
+	AC_DEFINE(HAVE_ATTRIBUTE_FUNCTION_ALIAS)
 	AC_DEFINE_UNQUOTED([RUBY_ALIAS_FUNCTION_TYPE(type, prot, name, args)],
 			   [type prot __attribute__(($rb_cv_gcc_function_alias(@%:@name)));])
 	AC_DEFINE_UNQUOTED([RUBY_ALIAS_FUNCTION_VOID(prot, name, args)],