diff --git a/include/cinttypes b/include/cinttypes
index 786692b8f..cfd763c98 100644
--- a/include/cinttypes
+++ b/include/cinttypes
@@ -247,7 +247,9 @@ _LIBCPP_BEGIN_NAMESPACE_STD
 
 using::imaxdiv_t;
 
+#undef imaxabs
 using::imaxabs;
+#undef imaxdiv
 using::imaxdiv;
 using::strtoimax;
 using::strtoumax;
diff --git a/include/cstdlib b/include/cstdlib
index 152b891de..298040e3f 100644
--- a/include/cstdlib
+++ b/include/cstdlib
@@ -131,14 +131,20 @@ using ::getenv;
 using ::system;
 using ::bsearch;
 using ::qsort;
+#undef abs
 using ::abs;
+#undef labs
 using ::labs;
 #ifndef _LIBCPP_HAS_NO_LONG_LONG
+#undef llabs
 using ::llabs;
 #endif // _LIBCPP_HAS_NO_LONG_LONG
+#undef div
 using ::div;
+#undef ldiv
 using ::ldiv;
 #ifndef _LIBCPP_HAS_NO_LONG_LONG
+#undef lldiv
 using ::lldiv;
 #endif // _LIBCPP_HAS_NO_LONG_LONG
 using ::mblen;