diff --git a/m4/namespaces.m4 b/m4/namespaces.m4
deleted file mode 100644
index d78dbe4..0000000
--- a/m4/namespaces.m4
+++ /dev/null
@@ -1,15 +0,0 @@
-# Checks whether the compiler implements namespaces
-AC_DEFUN([AC_CXX_NAMESPACES],
- [AC_CACHE_CHECK(whether the compiler implements namespaces,
-                 ac_cv_cxx_namespaces,
-                 [AC_LANG_SAVE
-                  AC_LANG_CPLUSPLUS
-                  AC_TRY_COMPILE([namespace Outer {
-                                    namespace Inner { int i = 0; }}],
-                                 [using namespace Outer::Inner; return i;],
-                                 ac_cv_cxx_namespaces=yes,
-                                 ac_cv_cxx_namespaces=no)
-                  AC_LANG_RESTORE])
-  if test "$ac_cv_cxx_namespaces" = yes; then
-    AC_DEFINE(HAVE_NAMESPACES, 1, [define if the compiler implements namespaces])
-  fi])
diff --git a/m4/stl_hash.m4 b/m4/stl_hash.m4
index a31baab..9572974 100644
--- a/m4/stl_hash.m4
+++ b/m4/stl_hash.m4
@@ -9,7 +9,7 @@
 
 # This also checks if unordered map exists.
 AC_DEFUN([AC_CXX_STL_HASH],
-  [AC_REQUIRE([AC_CXX_NAMESPACES])
+  [
    AC_MSG_CHECKING(the location of hash_map) 
    AC_LANG_SAVE
    AC_LANG_CPLUSPLUS