diff --git a/configure.ac b/configure.ac
index d5f1321be1..2cf34a64df 100644
--- a/configure.ac
+++ b/configure.ac
@@ -981,22 +981,6 @@ AC_CHECK_DECLS([setsid])
 
 AC_CHECK_DECLS([pipe2])
 
-AC_MSG_CHECKING([for __builtin_clzl])
-AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[ ]], [[
- (void) __builtin_clzl(0);
-  ]])],
- [ AC_MSG_RESULT([yes]); have_clzl=yes; AC_DEFINE([HAVE_BUILTIN_CLZL], [1], [Define this symbol if you have __builtin_clzl])],
- [ AC_MSG_RESULT([no]); have_clzl=no;]
-)
-
-AC_MSG_CHECKING([for __builtin_clzll])
-AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[ ]], [[
-  (void) __builtin_clzll(0);
-  ]])],
- [ AC_MSG_RESULT([yes]); have_clzll=yes; AC_DEFINE([HAVE_BUILTIN_CLZLL], [1], [Define this symbol if you have __builtin_clzll])],
- [ AC_MSG_RESULT([no]); have_clzll=no;]
-)
-
 dnl Check for malloc_info (for memory statistics information in getmemoryinfo)
 AC_MSG_CHECKING([for getmemoryinfo])
 AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <malloc.h>]],