autoconf/lib/autoconf/c.m4         |   24 ++++++++++++++++++++++++

 autoconf/lib/autoconf/functions.m4 |    4 +++-

 autoconf/lib/autoconf/lang.m4      |    7 +++++++

 3 files changed, 34 insertions(+), 1 deletions(-)

diff --git a/autoconf/lib/autoconf/c.m4 b/autoconf/lib/autoconf/c.m4

index 2a28a3b..f4c5f81 100644

--- a/autoconf/lib/autoconf/c.m4

+++ b/autoconf/lib/autoconf/c.m4

@@ -253,6 +253,25 @@ choke me

 ], [return $1 ();])])

+# AC_LANG_FUNC_LINK_TRY_GCC_BUILTIN(C)(FUNCTION)

+# ----------------------------------

+# This will test if function is available as

+# gcc3 builtin.

+#

+m4_define([AC_LANG_FUNC_LINK_TRY_GCC_BUILTIN(C)],

+[AC_LANG_PROGRAM(

+[#ifndef __GNUC__

+choke me

+#else

+#undef $1

+/* Declare this function with same prototype as __builtin_$1.

+  This removes warning about conflicting type with builtin */

+__typeof__(__builtin_$1) $1;

+

+__typeof__(__builtin_$1) *f = $1;

+#endif

+], [return f != __builtin_$1;])])

+

 # AC_LANG_BOOL_COMPILE_TRY(C)(PROLOGUE, EXPRESSION)

 # -------------------------------------------------

 # Return a program that is valid if EXPRESSION is nonzero.

@@ -321,6 +340,11 @@ m4_copy([AC_LANG_CALL(C)], [AC_LANG_CALL(C++)])

 m4_copy([AC_LANG_FUNC_LINK_TRY(C)], [AC_LANG_FUNC_LINK_TRY(C++)])

+# AC_LANG_FUNC_LINK_TRY_GCC_BUILTIN(C++)(FUNCTION)

+# ------------------------------------

+m4_copy([AC_LANG_FUNC_LINK_TRY_GCC_BUILTIN(C)], [AC_LANG_FUNC_LINK_TRY_GCC_BUILTIN(C++)])

+

+

 # AC_LANG_BOOL_COMPILE_TRY(C++)(PROLOGUE, EXPRESSION)

 # ---------------------------------------------------

 m4_copy([AC_LANG_BOOL_COMPILE_TRY(C)], [AC_LANG_BOOL_COMPILE_TRY(C++)])

diff --git a/autoconf/lib/autoconf/functions.m4 b/autoconf/lib/autoconf/functions.m4

index ec22aa9..d31bd12 100644

--- a/autoconf/lib/autoconf/functions.m4

+++ b/autoconf/lib/autoconf/functions.m4

@@ -69,7 +69,9 @@ AC_DEFUN([AC_CHECK_FUNC],

 AC_CACHE_CHECK([for $1], [ac_var],

 [AC_LINK_IFELSE([AC_LANG_FUNC_LINK_TRY([$1])],

 		[AS_VAR_SET([ac_var], [yes])],

-		[AS_VAR_SET([ac_var], [no])])])

+		[AC_LINK_IFELSE([AC_LANG_FUNC_LINK_TRY_GCC_BUILTIN([$1])],

+				[AS_VAR_SET([ac_var], [yes])],

+				[AS_VAR_SET([ac_var], [no])])])])

 AS_IF([test AS_VAR_GET([ac_var]) = yes], [$2], [$3])dnl

 AS_VAR_POPDEF([ac_var])dnl

 ])# AC_CHECK_FUNC

diff --git a/autoconf/lib/autoconf/lang.m4 b/autoconf/lib/autoconf/lang.m4

index 9816633..ee05287 100644

--- a/autoconf/lib/autoconf/lang.m4

+++ b/autoconf/lib/autoconf/lang.m4

@@ -254,6 +254,13 @@ AC_DEFUN([AC_LANG_FUNC_LINK_TRY],

 _AC_LANG_DISPATCH([$0], _AC_LANG, $@)])

+# AC_LANG_FUNC_LINK_TRY_GCC_BUILTIN(FUNCTION, TYPE)

+# -------------------------------

+AC_DEFUN([AC_LANG_FUNC_LINK_TRY_GCC_BUILTIN],

+[m4_ifval([$1], [], [m4_warn([syntax], [$0: no function given])])dnl

+_AC_LANG_DISPATCH([$0], _AC_LANG, $@)])

+

+

 # AC_LANG_BOOL_COMPILE_TRY(PROLOGUE, EXPRESSION)

 # ----------------------------------------------

 # Produce a program that compiles with success iff the boolean EXPRESSION