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-rw-r--r--third_party/glog/m4/ac_have_attribute.m416
-rw-r--r--third_party/glog/m4/ac_have_builtin_expect.m414
-rw-r--r--third_party/glog/m4/ac_have_sync_val_compare_and_swap.m414
-rw-r--r--third_party/glog/m4/ac_rwlock.m431
-rw-r--r--third_party/glog/m4/acx_pthread.m4363
-rw-r--r--third_party/glog/m4/google_namespace.m436
-rw-r--r--third_party/glog/m4/ltsugar.m4123
-rw-r--r--third_party/glog/m4/lt~obsolete.m498
-rw-r--r--third_party/glog/m4/namespaces.m415
-rw-r--r--third_party/glog/m4/pc_from_ucontext.m471
-rw-r--r--third_party/glog/m4/stl_namespace.m425
-rw-r--r--third_party/glog/m4/using_operator.m415
12 files changed, 821 insertions, 0 deletions
diff --git a/third_party/glog/m4/ac_have_attribute.m4 b/third_party/glog/m4/ac_have_attribute.m4
new file mode 100644
index 000000000000..19f4021e9901
--- /dev/null
+++ b/third_party/glog/m4/ac_have_attribute.m4
@@ -0,0 +1,16 @@
+AC_DEFUN([AX_C___ATTRIBUTE__], [
+  AC_MSG_CHECKING(for __attribute__)
+  AC_CACHE_VAL(ac_cv___attribute__, [
+    AC_TRY_COMPILE(
+      [#include <stdlib.h>
+       static void foo(void) __attribute__ ((unused));
+       void foo(void) { exit(1); }],
+      [],
+      ac_cv___attribute__=yes,
+      ac_cv___attribute__=no
+    )])
+  if test "$ac_cv___attribute__" = "yes"; then
+    AC_DEFINE(HAVE___ATTRIBUTE__, 1, [define if your compiler has __attribute__])
+  fi
+  AC_MSG_RESULT($ac_cv___attribute__)
+])
diff --git a/third_party/glog/m4/ac_have_builtin_expect.m4 b/third_party/glog/m4/ac_have_builtin_expect.m4
new file mode 100644
index 000000000000..e91b6fd987ed
--- /dev/null
+++ b/third_party/glog/m4/ac_have_builtin_expect.m4
@@ -0,0 +1,14 @@
+AC_DEFUN([AX_C___BUILTIN_EXPECT], [
+  AC_MSG_CHECKING(for __builtin_expect)
+  AC_CACHE_VAL(ac_cv___builtin_expect, [
+    AC_TRY_COMPILE(
+      [int foo(void) { if (__builtin_expect(0, 0)) return 1; return 0; }],
+      [],
+      ac_cv___builtin_expect=yes,
+      ac_cv___builtin_expect=no
+    )])
+  if test "$ac_cv___builtin_expect" = "yes"; then
+    AC_DEFINE(HAVE___BUILTIN_EXPECT, 1, [define if your compiler has __builtin_expect])
+  fi
+  AC_MSG_RESULT($ac_cv___builtin_expect)
+])
diff --git a/third_party/glog/m4/ac_have_sync_val_compare_and_swap.m4 b/third_party/glog/m4/ac_have_sync_val_compare_and_swap.m4
new file mode 100644
index 000000000000..88b027e23a29
--- /dev/null
+++ b/third_party/glog/m4/ac_have_sync_val_compare_and_swap.m4
@@ -0,0 +1,14 @@
+AC_DEFUN([AX_C___SYNC_VAL_COMPARE_AND_SWAP], [
+  AC_MSG_CHECKING(for __sync_val_compare_and_swap)
+  AC_CACHE_VAL(ac_cv___sync_val_compare_and_swap, [
+    AC_TRY_LINK(
+      [],
+      [int a; if (__sync_val_compare_and_swap(&a, 0, 1)) return 1; return 0;],
+      ac_cv___sync_val_compare_and_swap=yes,
+      ac_cv___sync_val_compare_and_swap=no
+    )])
+  if test "$ac_cv___sync_val_compare_and_swap" = "yes"; then
+    AC_DEFINE(HAVE___SYNC_VAL_COMPARE_AND_SWAP, 1, [define if your compiler has __sync_val_compare_and_swap])
+  fi
+  AC_MSG_RESULT($ac_cv___sync_val_compare_and_swap)
+])
diff --git a/third_party/glog/m4/ac_rwlock.m4 b/third_party/glog/m4/ac_rwlock.m4
new file mode 100644
index 000000000000..5065bcc1c5c2
--- /dev/null
+++ b/third_party/glog/m4/ac_rwlock.m4
@@ -0,0 +1,31 @@
+# TODO(csilvers): it would be better to actually try to link against
+# -pthreads, to make sure it defines these methods, but that may be
+# too hard, since pthread support is really tricky.
+
+# Check for support for pthread_rwlock_init() etc.
+# These aren't posix, but are widely supported.  To get them on linux,
+# you need to define _XOPEN_SOURCE first, so this check assumes your
+# application does that.
+#
+# Note: OS X (as of 6/1/06) seems to support pthread_rwlock, but
+# doesn't define PTHREAD_RWLOCK_INITIALIZER.  Therefore, we don't test
+# that particularly macro.  It's probably best if you don't use that
+# macro in your code either.
+
+AC_DEFUN([AC_RWLOCK],
+[AC_CACHE_CHECK(support for pthread_rwlock_* functions,
+ac_cv_rwlock,
+[AC_LANG_SAVE
+ AC_LANG_C
+ AC_TRY_COMPILE([#define _XOPEN_SOURCE 500
+                 #include <pthread.h>],
+		[pthread_rwlock_t l; pthread_rwlock_init(&l, NULL);
+                 pthread_rwlock_rdlock(&l); 
+                 return 0;],
+                ac_cv_rwlock=yes, ac_cv_rwlock=no)
+ AC_LANG_RESTORE
+])
+if test "$ac_cv_rwlock" = yes; then
+  AC_DEFINE(HAVE_RWLOCK,1,[define if the compiler implements pthread_rwlock_*])
+fi
+])
diff --git a/third_party/glog/m4/acx_pthread.m4 b/third_party/glog/m4/acx_pthread.m4
new file mode 100644
index 000000000000..2cf20de144a1
--- /dev/null
+++ b/third_party/glog/m4/acx_pthread.m4
@@ -0,0 +1,363 @@
+# This was retrieved from
+#    http://svn.0pointer.de/viewvc/trunk/common/acx_pthread.m4?revision=1277&root=avahi
+# See also (perhaps for new versions?)
+#    http://svn.0pointer.de/viewvc/trunk/common/acx_pthread.m4?root=avahi
+#
+# We've rewritten the inconsistency check code (from avahi), to work
+# more broadly.  In particular, it no longer assumes ld accepts -zdefs.
+# This caused a restructing of the code, but the functionality has only
+# changed a little.
+
+dnl @synopsis ACX_PTHREAD([ACTION-IF-FOUND[, ACTION-IF-NOT-FOUND]])
+dnl
+dnl @summary figure out how to build C programs using POSIX threads
+dnl
+dnl This macro figures out how to build C programs using POSIX threads.
+dnl It sets the PTHREAD_LIBS output variable to the threads library and
+dnl linker flags, and the PTHREAD_CFLAGS output variable to any special
+dnl C compiler flags that are needed. (The user can also force certain
+dnl compiler flags/libs to be tested by setting these environment
+dnl variables.)
+dnl
+dnl Also sets PTHREAD_CC to any special C compiler that is needed for
+dnl multi-threaded programs (defaults to the value of CC otherwise).
+dnl (This is necessary on AIX to use the special cc_r compiler alias.)
+dnl
+dnl NOTE: You are assumed to not only compile your program with these
+dnl flags, but also link it with them as well. e.g. you should link
+dnl with $PTHREAD_CC $CFLAGS $PTHREAD_CFLAGS $LDFLAGS ... $PTHREAD_LIBS
+dnl $LIBS
+dnl
+dnl If you are only building threads programs, you may wish to use
+dnl these variables in your default LIBS, CFLAGS, and CC:
+dnl
+dnl        LIBS="$PTHREAD_LIBS $LIBS"
+dnl        CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
+dnl        CC="$PTHREAD_CC"
+dnl
+dnl In addition, if the PTHREAD_CREATE_JOINABLE thread-attribute
+dnl constant has a nonstandard name, defines PTHREAD_CREATE_JOINABLE to
+dnl that name (e.g. PTHREAD_CREATE_UNDETACHED on AIX).
+dnl
+dnl ACTION-IF-FOUND is a list of shell commands to run if a threads
+dnl library is found, and ACTION-IF-NOT-FOUND is a list of commands to
+dnl run it if it is not found. If ACTION-IF-FOUND is not specified, the
+dnl default action will define HAVE_PTHREAD.
+dnl
+dnl Please let the authors know if this macro fails on any platform, or
+dnl if you have any other suggestions or comments. This macro was based
+dnl on work by SGJ on autoconf scripts for FFTW (www.fftw.org) (with
+dnl help from M. Frigo), as well as ac_pthread and hb_pthread macros
+dnl posted by Alejandro Forero Cuervo to the autoconf macro repository.
+dnl We are also grateful for the helpful feedback of numerous users.
+dnl
+dnl @category InstalledPackages
+dnl @author Steven G. Johnson <stevenj@alum.mit.edu>
+dnl @version 2006-05-29
+dnl @license GPLWithACException
+dnl 
+dnl Checks for GCC shared/pthread inconsistency based on work by
+dnl Marcin Owsiany <marcin@owsiany.pl>
+
+
+AC_DEFUN([ACX_PTHREAD], [
+AC_REQUIRE([AC_CANONICAL_HOST])
+AC_LANG_SAVE
+AC_LANG_C
+acx_pthread_ok=no
+
+# We used to check for pthread.h first, but this fails if pthread.h
+# requires special compiler flags (e.g. on True64 or Sequent).
+# It gets checked for in the link test anyway.
+
+# First of all, check if the user has set any of the PTHREAD_LIBS,
+# etcetera environment variables, and if threads linking works using
+# them:
+if test x"$PTHREAD_LIBS$PTHREAD_CFLAGS" != x; then
+        save_CFLAGS="$CFLAGS"
+        CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
+        save_LIBS="$LIBS"
+        LIBS="$PTHREAD_LIBS $LIBS"
+        AC_MSG_CHECKING([for pthread_join in LIBS=$PTHREAD_LIBS with CFLAGS=$PTHREAD_CFLAGS])
+        AC_TRY_LINK_FUNC(pthread_join, acx_pthread_ok=yes)
+        AC_MSG_RESULT($acx_pthread_ok)
+        if test x"$acx_pthread_ok" = xno; then
+                PTHREAD_LIBS=""
+                PTHREAD_CFLAGS=""
+        fi
+        LIBS="$save_LIBS"
+        CFLAGS="$save_CFLAGS"
+fi
+
+# We must check for the threads library under a number of different
+# names; the ordering is very important because some systems
+# (e.g. DEC) have both -lpthread and -lpthreads, where one of the
+# libraries is broken (non-POSIX).
+
+# Create a list of thread flags to try.  Items starting with a "-" are
+# C compiler flags, and other items are library names, except for "none"
+# which indicates that we try without any flags at all, and "pthread-config"
+# which is a program returning the flags for the Pth emulation library.
+
+acx_pthread_flags="pthreads none -Kthread -kthread lthread -pthread -pthreads -mthreads pthread --thread-safe -mt pthread-config"
+
+# The ordering *is* (sometimes) important.  Some notes on the
+# individual items follow:
+
+# pthreads: AIX (must check this before -lpthread)
+# none: in case threads are in libc; should be tried before -Kthread and
+#       other compiler flags to prevent continual compiler warnings
+# -Kthread: Sequent (threads in libc, but -Kthread needed for pthread.h)
+# -kthread: FreeBSD kernel threads (preferred to -pthread since SMP-able)
+# lthread: LinuxThreads port on FreeBSD (also preferred to -pthread)
+# -pthread: Linux/gcc (kernel threads), BSD/gcc (userland threads)
+# -pthreads: Solaris/gcc
+# -mthreads: Mingw32/gcc, Lynx/gcc
+# -mt: Sun Workshop C (may only link SunOS threads [-lthread], but it
+#      doesn't hurt to check since this sometimes defines pthreads too;
+#      also defines -D_REENTRANT)
+#      ... -mt is also the pthreads flag for HP/aCC
+# pthread: Linux, etcetera
+# --thread-safe: KAI C++
+# pthread-config: use pthread-config program (for GNU Pth library)
+
+case "${host_cpu}-${host_os}" in
+        *solaris*)
+
+        # On Solaris (at least, for some versions), libc contains stubbed
+        # (non-functional) versions of the pthreads routines, so link-based
+        # tests will erroneously succeed.  (We need to link with -pthreads/-mt/
+        # -lpthread.)  (The stubs are missing pthread_cleanup_push, or rather
+        # a function called by this macro, so we could check for that, but
+        # who knows whether they'll stub that too in a future libc.)  So,
+        # we'll just look for -pthreads and -lpthread first:
+
+        acx_pthread_flags="-pthreads pthread -mt -pthread $acx_pthread_flags"
+        ;;
+esac
+
+if test x"$acx_pthread_ok" = xno; then
+for flag in $acx_pthread_flags; do
+
+        case $flag in
+                none)
+                AC_MSG_CHECKING([whether pthreads work without any flags])
+                ;;
+
+                -*)
+                AC_MSG_CHECKING([whether pthreads work with $flag])
+                PTHREAD_CFLAGS="$flag"
+                ;;
+
+		pthread-config)
+		AC_CHECK_PROG(acx_pthread_config, pthread-config, yes, no)
+		if test x"$acx_pthread_config" = xno; then continue; fi
+		PTHREAD_CFLAGS="`pthread-config --cflags`"
+		PTHREAD_LIBS="`pthread-config --ldflags` `pthread-config --libs`"
+		;;
+
+                *)
+                AC_MSG_CHECKING([for the pthreads library -l$flag])
+                PTHREAD_LIBS="-l$flag"
+                ;;
+        esac
+
+        save_LIBS="$LIBS"
+        save_CFLAGS="$CFLAGS"
+        LIBS="$PTHREAD_LIBS $LIBS"
+        CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
+
+        # Check for various functions.  We must include pthread.h,
+        # since some functions may be macros.  (On the Sequent, we
+        # need a special flag -Kthread to make this header compile.)
+        # We check for pthread_join because it is in -lpthread on IRIX
+        # while pthread_create is in libc.  We check for pthread_attr_init
+        # due to DEC craziness with -lpthreads.  We check for
+        # pthread_cleanup_push because it is one of the few pthread
+        # functions on Solaris that doesn't have a non-functional libc stub.
+        # We try pthread_create on general principles.
+        AC_TRY_LINK([#include <pthread.h>],
+                    [pthread_t th; pthread_join(th, 0);
+                     pthread_attr_init(0); pthread_cleanup_push(0, 0);
+                     pthread_create(0,0,0,0); pthread_cleanup_pop(0); ],
+                    [acx_pthread_ok=yes])
+
+        LIBS="$save_LIBS"
+        CFLAGS="$save_CFLAGS"
+
+        AC_MSG_RESULT($acx_pthread_ok)
+        if test "x$acx_pthread_ok" = xyes; then
+                break;
+        fi
+
+        PTHREAD_LIBS=""
+        PTHREAD_CFLAGS=""
+done
+fi
+
+# Various other checks:
+if test "x$acx_pthread_ok" = xyes; then
+        save_LIBS="$LIBS"
+        LIBS="$PTHREAD_LIBS $LIBS"
+        save_CFLAGS="$CFLAGS"
+        CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
+
+        # Detect AIX lossage: JOINABLE attribute is called UNDETACHED.
+	AC_MSG_CHECKING([for joinable pthread attribute])
+	attr_name=unknown
+	for attr in PTHREAD_CREATE_JOINABLE PTHREAD_CREATE_UNDETACHED; do
+	    AC_TRY_LINK([#include <pthread.h>], [int attr=$attr; return attr;],
+                        [attr_name=$attr; break])
+	done
+        AC_MSG_RESULT($attr_name)
+        if test "$attr_name" != PTHREAD_CREATE_JOINABLE; then
+            AC_DEFINE_UNQUOTED(PTHREAD_CREATE_JOINABLE, $attr_name,
+                               [Define to necessary symbol if this constant
+                                uses a non-standard name on your system.])
+        fi
+
+        AC_MSG_CHECKING([if more special flags are required for pthreads])
+        flag=no
+        case "${host_cpu}-${host_os}" in
+            *-aix* | *-freebsd* | *-darwin*) flag="-D_THREAD_SAFE";;
+            *solaris* | *-osf* | *-hpux*) flag="-D_REENTRANT";;
+        esac
+        AC_MSG_RESULT(${flag})
+        if test "x$flag" != xno; then
+            PTHREAD_CFLAGS="$flag $PTHREAD_CFLAGS"
+        fi
+
+        LIBS="$save_LIBS"
+        CFLAGS="$save_CFLAGS"
+        # More AIX lossage: must compile with xlc_r or cc_r
+	if test x"$GCC" != xyes; then
+          AC_CHECK_PROGS(PTHREAD_CC, xlc_r cc_r, ${CC})
+        else
+          PTHREAD_CC=$CC
+	fi
+
+	# The next part tries to detect GCC inconsistency with -shared on some
+	# architectures and systems. The problem is that in certain
+	# configurations, when -shared is specified, GCC "forgets" to
+	# internally use various flags which are still necessary.
+	
+	#
+	# Prepare the flags
+	#
+	save_CFLAGS="$CFLAGS"
+	save_LIBS="$LIBS"
+	save_CC="$CC"
+	
+	# Try with the flags determined by the earlier checks.
+	#
+	# -Wl,-z,defs forces link-time symbol resolution, so that the
+	# linking checks with -shared actually have any value
+	#
+	# FIXME: -fPIC is required for -shared on many architectures,
+	# so we specify it here, but the right way would probably be to
+	# properly detect whether it is actually required.
+	CFLAGS="-shared -fPIC -Wl,-z,defs $CFLAGS $PTHREAD_CFLAGS"
+	LIBS="$PTHREAD_LIBS $LIBS"
+	CC="$PTHREAD_CC"
+	
+	# In order not to create several levels of indentation, we test
+	# the value of "$done" until we find the cure or run out of ideas.
+	done="no"
+	
+	# First, make sure the CFLAGS we added are actually accepted by our
+	# compiler.  If not (and OS X's ld, for instance, does not accept -z),
+	# then we can't do this test.
+	if test x"$done" = xno; then
+	   AC_MSG_CHECKING([whether to check for GCC pthread/shared inconsistencies])
+	   AC_TRY_LINK(,, , [done=yes])
+	
+	   if test "x$done" = xyes ; then
+	      AC_MSG_RESULT([no])
+	   else
+	      AC_MSG_RESULT([yes])
+	   fi
+	fi
+	
+	if test x"$done" = xno; then
+	   AC_MSG_CHECKING([whether -pthread is sufficient with -shared])
+	   AC_TRY_LINK([#include <pthread.h>],
+	      [pthread_t th; pthread_join(th, 0);
+	      pthread_attr_init(0); pthread_cleanup_push(0, 0);
+	      pthread_create(0,0,0,0); pthread_cleanup_pop(0); ],
+	      [done=yes])
+	   
+	   if test "x$done" = xyes; then
+	      AC_MSG_RESULT([yes])
+	   else
+	      AC_MSG_RESULT([no])
+	   fi
+	fi
+	
+	#
+	# Linux gcc on some architectures such as mips/mipsel forgets
+	# about -lpthread
+	#
+	if test x"$done" = xno; then
+	   AC_MSG_CHECKING([whether -lpthread fixes that])
+	   LIBS="-lpthread $PTHREAD_LIBS $save_LIBS"
+	   AC_TRY_LINK([#include <pthread.h>],
+	      [pthread_t th; pthread_join(th, 0);
+	      pthread_attr_init(0); pthread_cleanup_push(0, 0);
+	      pthread_create(0,0,0,0); pthread_cleanup_pop(0); ],
+	      [done=yes])
+	
+	   if test "x$done" = xyes; then
+	      AC_MSG_RESULT([yes])
+	      PTHREAD_LIBS="-lpthread $PTHREAD_LIBS"
+	   else
+	      AC_MSG_RESULT([no])
+	   fi
+	fi
+	#
+	# FreeBSD 4.10 gcc forgets to use -lc_r instead of -lc
+	#
+	if test x"$done" = xno; then
+	   AC_MSG_CHECKING([whether -lc_r fixes that])
+	   LIBS="-lc_r $PTHREAD_LIBS $save_LIBS"
+	   AC_TRY_LINK([#include <pthread.h>],
+	       [pthread_t th; pthread_join(th, 0);
+	        pthread_attr_init(0); pthread_cleanup_push(0, 0);
+	        pthread_create(0,0,0,0); pthread_cleanup_pop(0); ],
+	       [done=yes])
+	
+	   if test "x$done" = xyes; then
+	      AC_MSG_RESULT([yes])
+	      PTHREAD_LIBS="-lc_r $PTHREAD_LIBS"
+	   else
+	      AC_MSG_RESULT([no])
+	   fi
+	fi
+	if test x"$done" = xno; then
+	   # OK, we have run out of ideas
+	   AC_MSG_WARN([Impossible to determine how to use pthreads with shared libraries])
+	
+	   # so it's not safe to assume that we may use pthreads
+	   acx_pthread_ok=no
+	fi
+	
+	CFLAGS="$save_CFLAGS"
+	LIBS="$save_LIBS"
+	CC="$save_CC"
+else
+        PTHREAD_CC="$CC"
+fi
+
+AC_SUBST(PTHREAD_LIBS)
+AC_SUBST(PTHREAD_CFLAGS)
+AC_SUBST(PTHREAD_CC)
+
+# Finally, execute ACTION-IF-FOUND/ACTION-IF-NOT-FOUND:
+if test x"$acx_pthread_ok" = xyes; then
+        ifelse([$1],,AC_DEFINE(HAVE_PTHREAD,1,[Define if you have POSIX threads libraries and header files.]),[$1])
+        :
+else
+        acx_pthread_ok=no
+        $2
+fi
+AC_LANG_RESTORE
+])dnl ACX_PTHREAD
diff --git a/third_party/glog/m4/google_namespace.m4 b/third_party/glog/m4/google_namespace.m4
new file mode 100644
index 000000000000..79e0a6d42a6b
--- /dev/null
+++ b/third_party/glog/m4/google_namespace.m4
@@ -0,0 +1,36 @@
+# Allow users to override the namespace we define our application's classes in
+# Arg $1 is the default namespace to use if --enable-namespace isn't present.
+
+# In general, $1 should be 'google', so we put all our exported symbols in a
+# unique namespace that is not likely to conflict with anyone else.  However,
+# when it makes sense -- for instance, when publishing stl-like code -- you
+# may want to go with a different default, like 'std'.
+
+AC_DEFUN([AC_DEFINE_GOOGLE_NAMESPACE],
+  [google_namespace_default=[$1]
+   AC_ARG_ENABLE(namespace, [  --enable-namespace=FOO to define these Google
+                             classes in the FOO namespace. --disable-namespace
+                             to define them in the global namespace. Default
+                             is to define them in namespace $1.],
+                 [case "$enableval" in
+                    yes) google_namespace="$google_namespace_default" ;;
+                     no) google_namespace="" ;;
+                      *) google_namespace="$enableval" ;;
+                  esac],
+                 [google_namespace="$google_namespace_default"])
+   if test -n "$google_namespace"; then
+     ac_google_namespace="$google_namespace"
+     ac_google_start_namespace="namespace $google_namespace {"
+     ac_google_end_namespace="}"
+   else
+     ac_google_namespace=""
+     ac_google_start_namespace=""
+     ac_google_end_namespace=""
+   fi
+   AC_DEFINE_UNQUOTED(GOOGLE_NAMESPACE, $ac_google_namespace,
+                      Namespace for Google classes)
+   AC_DEFINE_UNQUOTED(_START_GOOGLE_NAMESPACE_, $ac_google_start_namespace,
+                      Puts following code inside the Google namespace)
+   AC_DEFINE_UNQUOTED(_END_GOOGLE_NAMESPACE_,  $ac_google_end_namespace,
+                      Stops putting the code inside the Google namespace)
+])
diff --git a/third_party/glog/m4/ltsugar.m4 b/third_party/glog/m4/ltsugar.m4
new file mode 100644
index 000000000000..9000a057d31d
--- /dev/null
+++ b/third_party/glog/m4/ltsugar.m4
@@ -0,0 +1,123 @@
+# ltsugar.m4 -- libtool m4 base layer.                         -*-Autoconf-*-
+#
+# Copyright (C) 2004, 2005, 2007, 2008 Free Software Foundation, Inc.
+# Written by Gary V. Vaughan, 2004
+#
+# This file is free software; the Free Software Foundation gives
+# unlimited permission to copy and/or distribute it, with or without
+# modifications, as long as this notice is preserved.
+
+# serial 6 ltsugar.m4
+
+# This is to help aclocal find these macros, as it can't see m4_define.
+AC_DEFUN([LTSUGAR_VERSION], [m4_if([0.1])])
+
+
+# lt_join(SEP, ARG1, [ARG2...])
+# -----------------------------
+# Produce ARG1SEPARG2...SEPARGn, omitting [] arguments and their
+# associated separator.
+# Needed until we can rely on m4_join from Autoconf 2.62, since all earlier
+# versions in m4sugar had bugs.
+m4_define([lt_join],
+[m4_if([$#], [1], [],
+       [$#], [2], [[$2]],
+       [m4_if([$2], [], [], [[$2]_])$0([$1], m4_shift(m4_shift($@)))])])
+m4_define([_lt_join],
+[m4_if([$#$2], [2], [],
+       [m4_if([$2], [], [], [[$1$2]])$0([$1], m4_shift(m4_shift($@)))])])
+
+
+# lt_car(LIST)
+# lt_cdr(LIST)
+# ------------
+# Manipulate m4 lists.
+# These macros are necessary as long as will still need to support
+# Autoconf-2.59 which quotes differently.
+m4_define([lt_car], [[$1]])
+m4_define([lt_cdr],
+[m4_if([$#], 0, [m4_fatal([$0: cannot be called without arguments])],
+       [$#], 1, [],
+       [m4_dquote(m4_shift($@))])])
+m4_define([lt_unquote], $1)
+
+
+# lt_append(MACRO-NAME, STRING, [SEPARATOR])
+# ------------------------------------------
+# Redefine MACRO-NAME to hold its former content plus `SEPARATOR'`STRING'.
+# Note that neither SEPARATOR nor STRING are expanded; they are appended
+# to MACRO-NAME as is (leaving the expansion for when MACRO-NAME is invoked).
+# No SEPARATOR is output if MACRO-NAME was previously undefined (different
+# than defined and empty).
+#
+# This macro is needed until we can rely on Autoconf 2.62, since earlier
+# versions of m4sugar mistakenly expanded SEPARATOR but not STRING.
+m4_define([lt_append],
+[m4_define([$1],
+	   m4_ifdef([$1], [m4_defn([$1])[$3]])[$2])])
+
+
+
+# lt_combine(SEP, PREFIX-LIST, INFIX, SUFFIX1, [SUFFIX2...])
+# ----------------------------------------------------------
+# Produce a SEP delimited list of all paired combinations of elements of
+# PREFIX-LIST with SUFFIX1 through SUFFIXn.  Each element of the list
+# has the form PREFIXmINFIXSUFFIXn.
+# Needed until we can rely on m4_combine added in Autoconf 2.62.
+m4_define([lt_combine],
+[m4_if(m4_eval([$# > 3]), [1],
+       [m4_pushdef([_Lt_sep], [m4_define([_Lt_sep], m4_defn([lt_car]))])]]dnl
+[[m4_foreach([_Lt_prefix], [$2],
+	     [m4_foreach([_Lt_suffix],
+		]m4_dquote(m4_dquote(m4_shift(m4_shift(m4_shift($@)))))[,
+	[_Lt_sep([$1])[]m4_defn([_Lt_prefix])[$3]m4_defn([_Lt_suffix])])])])])
+
+
+# lt_if_append_uniq(MACRO-NAME, VARNAME, [SEPARATOR], [UNIQ], [NOT-UNIQ])
+# -----------------------------------------------------------------------
+# Iff MACRO-NAME does not yet contain VARNAME, then append it (delimited
+# by SEPARATOR if supplied) and expand UNIQ, else NOT-UNIQ.
+m4_define([lt_if_append_uniq],
+[m4_ifdef([$1],
+	  [m4_if(m4_index([$3]m4_defn([$1])[$3], [$3$2$3]), [-1],
+		 [lt_append([$1], [$2], [$3])$4],
+		 [$5])],
+	  [lt_append([$1], [$2], [$3])$4])])
+
+
+# lt_dict_add(DICT, KEY, VALUE)
+# -----------------------------
+m4_define([lt_dict_add],
+[m4_define([$1($2)], [$3])])
+
+
+# lt_dict_add_subkey(DICT, KEY, SUBKEY, VALUE)
+# --------------------------------------------
+m4_define([lt_dict_add_subkey],
+[m4_define([$1($2:$3)], [$4])])
+
+
+# lt_dict_fetch(DICT, KEY, [SUBKEY])
+# ----------------------------------
+m4_define([lt_dict_fetch],
+[m4_ifval([$3],
+	m4_ifdef([$1($2:$3)], [m4_defn([$1($2:$3)])]),
+    m4_ifdef([$1($2)], [m4_defn([$1($2)])]))])
+
+
+# lt_if_dict_fetch(DICT, KEY, [SUBKEY], VALUE, IF-TRUE, [IF-FALSE])
+# -----------------------------------------------------------------
+m4_define([lt_if_dict_fetch],
+[m4_if(lt_dict_fetch([$1], [$2], [$3]), [$4],
+	[$5],
+    [$6])])
+
+
+# lt_dict_filter(DICT, [SUBKEY], VALUE, [SEPARATOR], KEY, [...])
+# --------------------------------------------------------------
+m4_define([lt_dict_filter],
+[m4_if([$5], [], [],
+  [lt_join(m4_quote(m4_default([$4], [[, ]])),
+           lt_unquote(m4_split(m4_normalize(m4_foreach(_Lt_key, lt_car([m4_shiftn(4, $@)]),
+		      [lt_if_dict_fetch([$1], _Lt_key, [$2], [$3], [_Lt_key ])])))))])[]dnl
+])
diff --git a/third_party/glog/m4/lt~obsolete.m4 b/third_party/glog/m4/lt~obsolete.m4
new file mode 100644
index 000000000000..c573da90c5cc
--- /dev/null
+++ b/third_party/glog/m4/lt~obsolete.m4
@@ -0,0 +1,98 @@
+# lt~obsolete.m4 -- aclocal satisfying obsolete definitions.    -*-Autoconf-*-
+#
+#   Copyright (C) 2004, 2005, 2007, 2009 Free Software Foundation, Inc.
+#   Written by Scott James Remnant, 2004.
+#
+# This file is free software; the Free Software Foundation gives
+# unlimited permission to copy and/or distribute it, with or without
+# modifications, as long as this notice is preserved.
+
+# serial 5 lt~obsolete.m4
+
+# These exist entirely to fool aclocal when bootstrapping libtool.
+#
+# In the past libtool.m4 has provided macros via AC_DEFUN (or AU_DEFUN)
+# which have later been changed to m4_define as they aren't part of the
+# exported API, or moved to Autoconf or Automake where they belong.
+#
+# The trouble is, aclocal is a bit thick.  It'll see the old AC_DEFUN
+# in /usr/share/aclocal/libtool.m4 and remember it, then when it sees us
+# using a macro with the same name in our local m4/libtool.m4 it'll
+# pull the old libtool.m4 in (it doesn't see our shiny new m4_define
+# and doesn't know about Autoconf macros at all.)
+#
+# So we provide this file, which has a silly filename so it's always
+# included after everything else.  This provides aclocal with the
+# AC_DEFUNs it wants, but when m4 processes it, it doesn't do anything
+# because those macros already exist, or will be overwritten later.
+# We use AC_DEFUN over AU_DEFUN for compatibility with aclocal-1.6. 
+#
+# Anytime we withdraw an AC_DEFUN or AU_DEFUN, remember to add it here.
+# Yes, that means every name once taken will need to remain here until
+# we give up compatibility with versions before 1.7, at which point
+# we need to keep only those names which we still refer to.
+
+# This is to help aclocal find these macros, as it can't see m4_define.
+AC_DEFUN([LTOBSOLETE_VERSION], [m4_if([1])])
+
+m4_ifndef([AC_LIBTOOL_LINKER_OPTION],	[AC_DEFUN([AC_LIBTOOL_LINKER_OPTION])])
+m4_ifndef([AC_PROG_EGREP],		[AC_DEFUN([AC_PROG_EGREP])])
+m4_ifndef([_LT_AC_PROG_ECHO_BACKSLASH],	[AC_DEFUN([_LT_AC_PROG_ECHO_BACKSLASH])])
+m4_ifndef([_LT_AC_SHELL_INIT],		[AC_DEFUN([_LT_AC_SHELL_INIT])])
+m4_ifndef([_LT_AC_SYS_LIBPATH_AIX],	[AC_DEFUN([_LT_AC_SYS_LIBPATH_AIX])])
+m4_ifndef([_LT_PROG_LTMAIN],		[AC_DEFUN([_LT_PROG_LTMAIN])])
+m4_ifndef([_LT_AC_TAGVAR],		[AC_DEFUN([_LT_AC_TAGVAR])])
+m4_ifndef([AC_LTDL_ENABLE_INSTALL],	[AC_DEFUN([AC_LTDL_ENABLE_INSTALL])])
+m4_ifndef([AC_LTDL_PREOPEN],		[AC_DEFUN([AC_LTDL_PREOPEN])])
+m4_ifndef([_LT_AC_SYS_COMPILER],	[AC_DEFUN([_LT_AC_SYS_COMPILER])])
+m4_ifndef([_LT_AC_LOCK],		[AC_DEFUN([_LT_AC_LOCK])])
+m4_ifndef([AC_LIBTOOL_SYS_OLD_ARCHIVE],	[AC_DEFUN([AC_LIBTOOL_SYS_OLD_ARCHIVE])])
+m4_ifndef([_LT_AC_TRY_DLOPEN_SELF],	[AC_DEFUN([_LT_AC_TRY_DLOPEN_SELF])])
+m4_ifndef([AC_LIBTOOL_PROG_CC_C_O],	[AC_DEFUN([AC_LIBTOOL_PROG_CC_C_O])])
+m4_ifndef([AC_LIBTOOL_SYS_HARD_LINK_LOCKS], [AC_DEFUN([AC_LIBTOOL_SYS_HARD_LINK_LOCKS])])
+m4_ifndef([AC_LIBTOOL_OBJDIR],		[AC_DEFUN([AC_LIBTOOL_OBJDIR])])
+m4_ifndef([AC_LTDL_OBJDIR],		[AC_DEFUN([AC_LTDL_OBJDIR])])
+m4_ifndef([AC_LIBTOOL_PROG_LD_HARDCODE_LIBPATH], [AC_DEFUN([AC_LIBTOOL_PROG_LD_HARDCODE_LIBPATH])])
+m4_ifndef([AC_LIBTOOL_SYS_LIB_STRIP],	[AC_DEFUN([AC_LIBTOOL_SYS_LIB_STRIP])])
+m4_ifndef([AC_PATH_MAGIC],		[AC_DEFUN([AC_PATH_MAGIC])])
+m4_ifndef([AC_PROG_LD_GNU],		[AC_DEFUN([AC_PROG_LD_GNU])])
+m4_ifndef([AC_PROG_LD_RELOAD_FLAG],	[AC_DEFUN([AC_PROG_LD_RELOAD_FLAG])])
+m4_ifndef([AC_DEPLIBS_CHECK_METHOD],	[AC_DEFUN([AC_DEPLIBS_CHECK_METHOD])])
+m4_ifndef([AC_LIBTOOL_PROG_COMPILER_NO_RTTI], [AC_DEFUN([AC_LIBTOOL_PROG_COMPILER_NO_RTTI])])
+m4_ifndef([AC_LIBTOOL_SYS_GLOBAL_SYMBOL_PIPE], [AC_DEFUN([AC_LIBTOOL_SYS_GLOBAL_SYMBOL_PIPE])])
+m4_ifndef([AC_LIBTOOL_PROG_COMPILER_PIC], [AC_DEFUN([AC_LIBTOOL_PROG_COMPILER_PIC])])
+m4_ifndef([AC_LIBTOOL_PROG_LD_SHLIBS],	[AC_DEFUN([AC_LIBTOOL_PROG_LD_SHLIBS])])
+m4_ifndef([AC_LIBTOOL_POSTDEP_PREDEP],	[AC_DEFUN([AC_LIBTOOL_POSTDEP_PREDEP])])
+m4_ifndef([LT_AC_PROG_EGREP],		[AC_DEFUN([LT_AC_PROG_EGREP])])
+m4_ifndef([LT_AC_PROG_SED],		[AC_DEFUN([LT_AC_PROG_SED])])
+m4_ifndef([_LT_CC_BASENAME],		[AC_DEFUN([_LT_CC_BASENAME])])
+m4_ifndef([_LT_COMPILER_BOILERPLATE],	[AC_DEFUN([_LT_COMPILER_BOILERPLATE])])
+m4_ifndef([_LT_LINKER_BOILERPLATE],	[AC_DEFUN([_LT_LINKER_BOILERPLATE])])
+m4_ifndef([_AC_PROG_LIBTOOL],		[AC_DEFUN([_AC_PROG_LIBTOOL])])
+m4_ifndef([AC_LIBTOOL_SETUP],		[AC_DEFUN([AC_LIBTOOL_SETUP])])
+m4_ifndef([_LT_AC_CHECK_DLFCN],		[AC_DEFUN([_LT_AC_CHECK_DLFCN])])
+m4_ifndef([AC_LIBTOOL_SYS_DYNAMIC_LINKER],	[AC_DEFUN([AC_LIBTOOL_SYS_DYNAMIC_LINKER])])
+m4_ifndef([_LT_AC_TAGCONFIG],		[AC_DEFUN([_LT_AC_TAGCONFIG])])
+m4_ifndef([AC_DISABLE_FAST_INSTALL],	[AC_DEFUN([AC_DISABLE_FAST_INSTALL])])
+m4_ifndef([_LT_AC_LANG_CXX],		[AC_DEFUN([_LT_AC_LANG_CXX])])
+m4_ifndef([_LT_AC_LANG_F77],		[AC_DEFUN([_LT_AC_LANG_F77])])
+m4_ifndef([_LT_AC_LANG_GCJ],		[AC_DEFUN([_LT_AC_LANG_GCJ])])
+m4_ifndef([AC_LIBTOOL_LANG_C_CONFIG],	[AC_DEFUN([AC_LIBTOOL_LANG_C_CONFIG])])
+m4_ifndef([_LT_AC_LANG_C_CONFIG],	[AC_DEFUN([_LT_AC_LANG_C_CONFIG])])
+m4_ifndef([AC_LIBTOOL_LANG_CXX_CONFIG],	[AC_DEFUN([AC_LIBTOOL_LANG_CXX_CONFIG])])
+m4_ifndef([_LT_AC_LANG_CXX_CONFIG],	[AC_DEFUN([_LT_AC_LANG_CXX_CONFIG])])
+m4_ifndef([AC_LIBTOOL_LANG_F77_CONFIG],	[AC_DEFUN([AC_LIBTOOL_LANG_F77_CONFIG])])
+m4_ifndef([_LT_AC_LANG_F77_CONFIG],	[AC_DEFUN([_LT_AC_LANG_F77_CONFIG])])
+m4_ifndef([AC_LIBTOOL_LANG_GCJ_CONFIG],	[AC_DEFUN([AC_LIBTOOL_LANG_GCJ_CONFIG])])
+m4_ifndef([_LT_AC_LANG_GCJ_CONFIG],	[AC_DEFUN([_LT_AC_LANG_GCJ_CONFIG])])
+m4_ifndef([AC_LIBTOOL_LANG_RC_CONFIG],	[AC_DEFUN([AC_LIBTOOL_LANG_RC_CONFIG])])
+m4_ifndef([_LT_AC_LANG_RC_CONFIG],	[AC_DEFUN([_LT_AC_LANG_RC_CONFIG])])
+m4_ifndef([AC_LIBTOOL_CONFIG],		[AC_DEFUN([AC_LIBTOOL_CONFIG])])
+m4_ifndef([_LT_AC_FILE_LTDLL_C],	[AC_DEFUN([_LT_AC_FILE_LTDLL_C])])
+m4_ifndef([_LT_REQUIRED_DARWIN_CHECKS],	[AC_DEFUN([_LT_REQUIRED_DARWIN_CHECKS])])
+m4_ifndef([_LT_AC_PROG_CXXCPP],		[AC_DEFUN([_LT_AC_PROG_CXXCPP])])
+m4_ifndef([_LT_PREPARE_SED_QUOTE_VARS],	[AC_DEFUN([_LT_PREPARE_SED_QUOTE_VARS])])
+m4_ifndef([_LT_PROG_ECHO_BACKSLASH],	[AC_DEFUN([_LT_PROG_ECHO_BACKSLASH])])
+m4_ifndef([_LT_PROG_F77],		[AC_DEFUN([_LT_PROG_F77])])
+m4_ifndef([_LT_PROG_FC],		[AC_DEFUN([_LT_PROG_FC])])
+m4_ifndef([_LT_PROG_CXX],		[AC_DEFUN([_LT_PROG_CXX])])
diff --git a/third_party/glog/m4/namespaces.m4 b/third_party/glog/m4/namespaces.m4
new file mode 100644
index 000000000000..d78dbe4cc2e4
--- /dev/null
+++ b/third_party/glog/m4/namespaces.m4
@@ -0,0 +1,15 @@
+# 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/third_party/glog/m4/pc_from_ucontext.m4 b/third_party/glog/m4/pc_from_ucontext.m4
new file mode 100644
index 000000000000..daffddb536fd
--- /dev/null
+++ b/third_party/glog/m4/pc_from_ucontext.m4
@@ -0,0 +1,71 @@
+# We want to access the "PC" (Program Counter) register from a struct
+# ucontext.  Every system has its own way of doing that.  We try all the
+# possibilities we know about.  Note REG_PC should come first (REG_RIP
+# is also defined on solaris, but does the wrong thing).
+
+# OpenBSD doesn't have ucontext.h, but we can get PC from ucontext_t
+# by using signal.h.
+
+# The first argument of AC_PC_FROM_UCONTEXT will be invoked when we
+# cannot find a way to obtain PC from ucontext.
+
+AC_DEFUN([AC_PC_FROM_UCONTEXT],
+  [AC_CHECK_HEADERS(ucontext.h)
+   AC_CHECK_HEADERS(sys/ucontext.h)       # ucontext on OS X 10.6 (at least)
+   AC_MSG_CHECKING([how to access the program counter from a struct ucontext])
+   pc_fields="           uc_mcontext.gregs[[REG_PC]]"  # Solaris x86 (32 + 64 bit)
+   pc_fields="$pc_fields uc_mcontext.gregs[[REG_EIP]]" # Linux (i386)
+   pc_fields="$pc_fields uc_mcontext.gregs[[REG_RIP]]" # Linux (x86_64)
+   pc_fields="$pc_fields uc_mcontext.sc_ip"            # Linux (ia64)
+   pc_fields="$pc_fields uc_mcontext.uc_regs->gregs[[PT_NIP]]" # Linux (ppc)
+   pc_fields="$pc_fields uc_mcontext.gregs[[R15]]"     # Linux (arm old [untested])
+   pc_fields="$pc_fields uc_mcontext.arm_pc"           # Linux (arm new [untested])
+   pc_fields="$pc_fields uc_mcontext.mc_eip"           # FreeBSD (i386)
+   pc_fields="$pc_fields uc_mcontext.mc_rip"           # FreeBSD (x86_64 [untested])
+   pc_fields="$pc_fields uc_mcontext.__gregs[[_REG_EIP]]"  # NetBSD (i386)
+   pc_fields="$pc_fields uc_mcontext.__gregs[[_REG_RIP]]"  # NetBSD (x86_64)
+   pc_fields="$pc_fields uc_mcontext->ss.eip"          # OS X (i386, <=10.4)
+   pc_fields="$pc_fields uc_mcontext->__ss.__eip"      # OS X (i386, >=10.5)
+   pc_fields="$pc_fields uc_mcontext->ss.rip"          # OS X (x86_64)
+   pc_fields="$pc_fields uc_mcontext->__ss.__rip"      # OS X (>=10.5 [untested])
+   pc_fields="$pc_fields uc_mcontext->ss.srr0"         # OS X (ppc, ppc64 [untested])
+   pc_fields="$pc_fields uc_mcontext->__ss.__srr0"     # OS X (>=10.5 [untested])
+   pc_field_found=false
+   for pc_field in $pc_fields; do
+     if ! $pc_field_found; then
+       if test "x$ac_cv_header_sys_ucontext_h" = xyes; then
+         AC_TRY_COMPILE([#define _GNU_SOURCE 1
+                         #include <sys/ucontext.h>],
+                        [ucontext_t u; return u.$pc_field == 0;],
+                        AC_DEFINE_UNQUOTED(PC_FROM_UCONTEXT, $pc_field,
+                                           How to access the PC from a struct ucontext)
+                        AC_MSG_RESULT([$pc_field])
+                        pc_field_found=true)
+       else
+         AC_TRY_COMPILE([#define _GNU_SOURCE 1
+                         #include <ucontext.h>],
+                        [ucontext_t u; return u.$pc_field == 0;],
+                        AC_DEFINE_UNQUOTED(PC_FROM_UCONTEXT, $pc_field,
+                                           How to access the PC from a struct ucontext)
+                        AC_MSG_RESULT([$pc_field])
+                        pc_field_found=true)
+       fi
+     fi
+   done
+   if ! $pc_field_found; then
+     pc_fields="           sc_eip"  # OpenBSD (i386)
+     pc_fields="$pc_fields sc_rip"  # OpenBSD (x86_64)
+     for pc_field in $pc_fields; do
+       if ! $pc_field_found; then
+         AC_TRY_COMPILE([#include <signal.h>],
+                        [ucontext_t u; return u.$pc_field == 0;],
+                        AC_DEFINE_UNQUOTED(PC_FROM_UCONTEXT, $pc_field,
+                                           How to access the PC from a struct ucontext)
+                        AC_MSG_RESULT([$pc_field])
+                        pc_field_found=true)
+       fi
+     done
+   fi
+   if ! $pc_field_found; then
+     [$1]
+   fi])
diff --git a/third_party/glog/m4/stl_namespace.m4 b/third_party/glog/m4/stl_namespace.m4
new file mode 100644
index 000000000000..989ad80696a3
--- /dev/null
+++ b/third_party/glog/m4/stl_namespace.m4
@@ -0,0 +1,25 @@
+# We check what namespace stl code like vector expects to be executed in
+
+AC_DEFUN([AC_CXX_STL_NAMESPACE],
+  [AC_CACHE_CHECK(
+      what namespace STL code is in,
+      ac_cv_cxx_stl_namespace,
+      [AC_REQUIRE([AC_CXX_NAMESPACES])
+      AC_LANG_SAVE
+      AC_LANG_CPLUSPLUS
+      AC_TRY_COMPILE([#include <vector>],
+                     [vector<int> t; return 0;],
+                     ac_cv_cxx_stl_namespace=none)
+      AC_TRY_COMPILE([#include <vector>],
+                     [std::vector<int> t; return 0;],
+                     ac_cv_cxx_stl_namespace=std)
+      AC_LANG_RESTORE])
+   if test "$ac_cv_cxx_stl_namespace" = none; then
+      AC_DEFINE(STL_NAMESPACE,,
+                [the namespace where STL code like vector<> is defined])
+   fi
+   if test "$ac_cv_cxx_stl_namespace" = std; then
+      AC_DEFINE(STL_NAMESPACE,std,
+                [the namespace where STL code like vector<> is defined])
+   fi
+])
diff --git a/third_party/glog/m4/using_operator.m4 b/third_party/glog/m4/using_operator.m4
new file mode 100644
index 000000000000..95a9951eb346
--- /dev/null
+++ b/third_party/glog/m4/using_operator.m4
@@ -0,0 +1,15 @@
+AC_DEFUN([AC_CXX_USING_OPERATOR],
+  [AC_CACHE_CHECK(
+      whether compiler supports using ::operator<<,
+      ac_cv_cxx_using_operator,
+      [AC_LANG_SAVE
+       AC_LANG_CPLUSPLUS
+       AC_TRY_COMPILE([#include <iostream>
+                       std::ostream& operator<<(std::ostream&, struct s);],
+                      [using ::operator<<; return 0;],
+                      ac_cv_cxx_using_operator=1,
+		      ac_cv_cxx_using_operator=0)
+      AC_LANG_RESTORE])
+  if test "$ac_cv_cxx_using_operator" = 1; then
+    AC_DEFINE(HAVE_USING_OPERATOR, 1, [define if the compiler supports using expression for operator])
+  fi])