configure: Get rid of no longer needed __builtin_clz check.

configure

@@ -19490,39 +19490,6 @@ done
 
 LIBS="$ac_save_LIBS"
 
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for __builtin_clz" >&5
-$as_echo_n "checking for __builtin_clz... " >&6; }
-if ${ac_cv_have___builtin_clz+:} false; then :
-  $as_echo_n "(cached) " >&6
-else
-  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
-/* end confdefs.h.  */
-
-int
-main ()
-{
-return __builtin_clz(1)
-  ;
-  return 0;
-}
-_ACEOF
-if ac_fn_c_try_link "$LINENO"; then :
-  ac_cv_have___builtin_clz="yes"
-else
-  ac_cv_have___builtin_clz="no"
-fi
-rm -f core conftest.err conftest.$ac_objext \
-    conftest$ac_exeext conftest.$ac_ext
-fi
-{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_have___builtin_clz" >&5
-$as_echo "$ac_cv_have___builtin_clz" >&6; }
-if test "$ac_cv_have___builtin_clz" = "yes"
-then
-
-$as_echo "#define HAVE___BUILTIN_CLZ 1" >>confdefs.h
-
-fi
-
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for __builtin_popcount" >&5
 $as_echo_n "checking for __builtin_popcount... " >&6; }
 if ${ac_cv_have___builtin_popcount+:} false; then :

configure.ac

@@ -2738,15 +2738,6 @@ AC_CHECK_FUNCS(\
 )
 LIBS="$ac_save_LIBS"
 
-dnl Check for __builtin_clz
-AC_CACHE_CHECK([for __builtin_clz], ac_cv_have___builtin_clz,
-               AC_LINK_IFELSE([AC_LANG_PROGRAM(,[[return __builtin_clz(1)]])],
-               [ac_cv_have___builtin_clz="yes"], [ac_cv_have___builtin_clz="no"]))
-if test "$ac_cv_have___builtin_clz" = "yes"
-then
-    AC_DEFINE(HAVE___BUILTIN_CLZ, 1, [Define to 1 if you have the `__builtin_clz' built-in function.])
-fi
-
 dnl Check for __builtin_popcount
 AC_CACHE_CHECK([for __builtin_popcount], ac_cv_have___builtin_popcount,
                AC_LINK_IFELSE([AC_LANG_PROGRAM(,[[return __builtin_popcount(1)]])],

include/config.h.in

@@ -1304,9 +1304,6 @@
 /* Define to 1 if you have the `_spawnvp' function. */
 #undef HAVE__SPAWNVP
 
-/* Define to 1 if you have the `__builtin_clz' built-in function. */
-#undef HAVE___BUILTIN_CLZ
-
 /* Define to 1 if you have the `__builtin_popcount' built-in function. */
 #undef HAVE___BUILTIN_POPCOUNT