Bring the script out of the dark ages and into modern autoconfness.

llvm-svn: 16415
diff --git a/llvm/autoconf/m4/cxx_std_iterator.m4 b/llvm/autoconf/m4/cxx_std_iterator.m4
index 46665f2..578dcc4 100644
--- a/llvm/autoconf/m4/cxx_std_iterator.m4
+++ b/llvm/autoconf/m4/cxx_std_iterator.m4
@@ -4,14 +4,16 @@
 [AC_CACHE_CHECK(whether the compiler has the standard iterator,
 ac_cv_cxx_have_std_iterator,
 [AC_REQUIRE([AC_CXX_NAMESPACES])
-  AC_LANG_SAVE
-  AC_LANG_CPLUSPLUS
-  AC_TRY_COMPILE([#include <iterator>
+  AC_LANG_PUSH([C++])
+  AC_COMPILE_IFELSE([AC_LANG_PROGRAM(
+    [[#include <iterator>
 #ifdef HAVE_NAMESPACES
 using namespace std;
-#endif],[iterator<int,int,int> t; return 0;],
-  ac_cv_cxx_have_std_iterator=yes, ac_cv_cxx_have_std_iterator=no)
-  AC_LANG_RESTORE
+#endif]],
+  [[iterator<int,int,int> t; return 0;]])],
+  ac_cv_cxx_have_std_iterator=yes, 
+  ac_cv_cxx_have_std_iterator=no)
+  AC_LANG_POP([C++])
 ])
 HAVE_STD_ITERATOR=0
 if test "$ac_cv_cxx_have_std_iterator" = yes