--- a/configure.ac	Fri Mar 18 13:37:33 2016 -0400
+++ b/configure.ac	Fri Mar 18 11:01:02 2016 -0700
@@ -364,20 +364,12 @@
 
 ### Determine which C++ compiler to use (we expect to find g++).
 
-## Note that OCTAVE_PROG_CXX_CXX11 must come before AC_PROG_CXXCPP since
-## the later uses the value of CXX which may be modified by the first.
-
 AC_PROG_CXX
-OCTAVE_PROG_CXX_CXX11
 AC_PROG_CXXCPP
 
 ### Determine which C compiler to use (we expect to find gcc).
 
-## Note that OCTAVE_PROG_CC_C11 must come before AC_PROG_CPP since
-## the later uses the value of CC which may be modified by the first.
-
 AC_PROG_CC
-OCTAVE_PROG_CC_C11
 AC_PROG_CPP
 AC_PROG_GCC_TRADITIONAL
 

--- a/m4/prog_c.m4	Fri Mar 18 13:37:33 2016 -0400
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,282 +0,0 @@
-# Copyright (C) 2001-2016 Free Software Foundation, Inc.
-#
-#
-# This is pretty much copy and paste of the unreleased autoconf macros
-# (where it is named AC_PROG_CXX_CXX11).  Once we are dependent on
-# autoconf version with that macro, we can simply change to use that
-# one instead.  Copied from autoconf commit 04be2b7a (2016/02/06)
-#
-#
-# This file is part of Autoconf.  This program is free
-# software; you can redistribute it and/or modify it under the
-# terms of the GNU General Public License as published by the
-# Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
-#
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, see <http://www.gnu.org/licenses/>.
-
-# OCTAVE_PROG_CC_C11 ([ACTION-IF-AVAILABLE], [ACTION-IF-UNAVAILABLE])
-# ----------------------------------------------------------------
-# If the C compiler is not in ISO C11 mode by default, try to add an
-# option to output variable CC to make it so.  This macro tries
-# various options that select ISO C11 on some system or another.  It
-# considers the compiler to be in ISO C11 mode if it handles _Alignas,
-# _Alignof, _Noreturn, _Static_assert, UTF-8 string literals,
-# duplicate typedefs, and anonymous structures and unions.
-AC_DEFUN([OCTAVE_PROG_CC_C11],
-[_OCTAVE_C_STD_TRY([c11],
-[_OCTAVE_C_C99_TEST_HEADER[
-#include <stddef.h>
-// Check _Alignas.
-char _Alignas (double) aligned_as_double;
-char _Alignas (0) no_special_alignment;
-extern char aligned_as_int;
-char _Alignas (0) _Alignas (int) aligned_as_int;
-
-// Check _Alignof.
-enum
-{
-  int_alignment = _Alignof (int),
-  int_array_alignment = _Alignof (int[100]),
-  char_alignment = _Alignof (char)
-};
-_Static_assert (0 < -_Alignof (int), "_Alignof is signed");
-
-// Check _Noreturn.
-int _Noreturn does_not_return (void) { for (;;) continue; }
-
-// Check _Static_assert.
-struct test_static_assert
-{
-  int x;
-  _Static_assert (sizeof (int) <= sizeof (long int),
-                  "_Static_assert does not work in struct");
-  long int y;
-};
-
-// Check UTF-8 literals.
-#define u8 syntax error!
-char const utf8_literal[] = u8"happens to be ASCII" "another string";
-
-// Check duplicate typedefs.
-typedef long *long_ptr;
-typedef long int *long_ptr;
-typedef long_ptr long_ptr;
-
-// Anonymous structures and unions -- taken from C11 6.7.2.1 Example 1.
-struct anonymous
-{
-  union {
-    struct { int i; int j; };
-    struct { int k; long int l; } w;
-  };
-  int m;
-} v1;
-]],
-[_OCTAVE_C_C99_TEST_BODY[
-  v1.i = 2;
-  v1.w.k = 5;
-  // FIXME: Octave-specific change, this feature test is modified from the
-  // original Autoconf source. The address-of operator is not an integral
-  // constant expression and cannot be used with _Static_assert.
-  _Static_assert (offsetof(struct anonymous, i)
-                  == offsetof(struct anonymous, w.k),
-                  "Anonymous union alignment botch");
-]],
-dnl Try
-dnl GCC		-std=gnu11 (unused restrictive mode: -std=c11)
-dnl with extended modes being tried first.
-dnl
-dnl Do not try -qlanglvl=extc1x, because IBM XL C V12.1 (the latest version as
-dnl of September 2012) does not pass the C11 test.  For now, try extc1x when
-dnl compiling the C99 test instead, since it enables _Static_assert and
-dnl _Noreturn, which is a win.  If -qlanglvl=extc11 or -qlanglvl=extc1x passes
-dnl the C11 test in some future version of IBM XL C, we'll add it here,
-dnl preferably extc11.
-[[-std=gnu11]], [$1], [$2])[]dnl
-])# OCTAVE_PROG_CC_C11
-
-
-# _OCTAVE_C_STD_TRY(STANDARD, TEST-PROLOGUE, TEST-BODY, OPTION-LIST,
-#		ACTION-IF-AVAILABLE, ACTION-IF-UNAVAILABLE)
-# --------------------------------------------------------------
-# Check whether the C compiler accepts features of STANDARD (e.g `c89', `c99')
-# by trying to compile a program of TEST-PROLOGUE and TEST-BODY.  If this fails,
-# try again with each compiler option in the space-separated OPTION-LIST; if one
-# helps, append it to CC.  If eventually successful, run ACTION-IF-AVAILABLE,
-# else ACTION-IF-UNAVAILABLE.
-AC_DEFUN([_OCTAVE_C_STD_TRY],
-[AC_MSG_CHECKING([for $CC option to enable ]m4_translit($1, [c], [C])[ features])
-AC_CACHE_VAL(ac_cv_prog_cc_$1,
-[ac_cv_prog_cc_$1=no
-ac_save_CC=$CC
-AC_LANG_CONFTEST([AC_LANG_PROGRAM([$2], [$3])])
-for ac_arg in '' $4
-do
-  CC="$ac_save_CC $ac_arg"
-  _AC_COMPILE_IFELSE([], [ac_cv_prog_cc_$1=$ac_arg])
-  test "x$ac_cv_prog_cc_$1" != "xno" && break
-done
-rm -f conftest.$ac_ext
-CC=$ac_save_CC
-])# AC_CACHE_VAL
-ac_prog_cc_stdc_options=
-case "x$ac_cv_prog_cc_$1" in
-  x)
-    AC_MSG_RESULT([none needed]) ;;
-  xno)
-    AC_MSG_RESULT([unsupported]) ;;
-  *)
-    ac_prog_cc_stdc_options=" $ac_cv_prog_cc_$1"
-    CC=$CC$ac_prog_cc_stdc_options
-    AC_MSG_RESULT([$ac_cv_prog_cc_$1]) ;;
-esac
-AS_IF([test "x$ac_cv_prog_cc_$1" != xno], [$5], [$6])
-])# _OCTAVE_C_STD_TRY
-
-# _OCTAVE_C_C99_TEST_HEADER
-# ---------------------
-# A C header suitable for testing for C99.
-AC_DEFUN([_OCTAVE_C_C99_TEST_HEADER],
-[[#include <stdarg.h>
-#include <stdbool.h>
-#include <stdlib.h>
-#include <wchar.h>
-#include <stdio.h>
-
-// Check varargs macros.  These examples are taken from C99 6.10.3.5.
-#define debug(...) fprintf (stderr, __VA_ARGS__)
-#define showlist(...) puts (#__VA_ARGS__)
-#define report(test,...) ((test) ? puts (#test) : printf (__VA_ARGS__))
-static void
-test_varargs_macros (void)
-{
-  int x = 1234;
-  int y = 5678;
-  debug ("Flag");
-  debug ("X = %d\n", x);
-  showlist (The first, second, and third items.);
-  report (x>y, "x is %d but y is %d", x, y);
-}
-
-// Check long long types.
-#define BIG64 18446744073709551615ull
-#define BIG32 4294967295ul
-#define BIG_OK (BIG64 / BIG32 == 4294967297ull && BIG64 % BIG32 == 0)
-#if !BIG_OK
-  your preprocessor is broken;
-#endif
-#if BIG_OK
-#else
-  your preprocessor is broken;
-#endif
-static long long int bignum = -9223372036854775807LL;
-static unsigned long long int ubignum = BIG64;
-
-struct incomplete_array
-{
-  int datasize;
-  double data[];
-};
-
-struct named_init {
-  int number;
-  const wchar_t *name;
-  double average;
-};
-
-typedef const char *ccp;
-
-static inline int
-test_restrict (ccp restrict text)
-{
-  // See if C++-style comments work.
-  // Iterate through items via the restricted pointer.
-  // Also check for declarations in for loops.
-  for (unsigned int i = 0; *(text+i) != '\0'; ++i)
-    continue;
-  return 0;
-}
-
-// Check varargs and va_copy.
-static bool
-test_varargs (const char *format, ...)
-{
-  va_list args;
-  va_start (args, format);
-  va_list args_copy;
-  va_copy (args_copy, args);
-
-  const char *str = "";
-  int number = 0;
-  float fnumber = 0;
-
-  while (*format)
-    {
-      switch (*format++)
-	{
-	case 's': // string
-	  str = va_arg (args_copy, const char *);
-	  break;
-	case 'd': // int
-	  number = va_arg (args_copy, int);
-	  break;
-	case 'f': // float
-	  fnumber = va_arg (args_copy, double);
-	  break;
-	default:
-	  break;
-	}
-    }
-  va_end (args_copy);
-  va_end (args);
-
-  return *str && number && fnumber;
-}]])# _OCTAVE_C_C99_TEST_HEADER
-
-# _OCTAVE_C_C99_TEST_BODY
-# -------------------
-# A C body suitable for testing for C99, assuming the corresponding header.
-AC_DEFUN([_OCTAVE_C_C99_TEST_BODY],
-[[
-  // Check bool.
-  _Bool success = false;
-
-  // Check restrict.
-  if (test_restrict ("String literal") == 0)
-    success = true;
-  char *restrict newvar = "Another string";
-
-  // Check varargs.
-  success &= test_varargs ("s, d' f .", "string", 65, 34.234);
-  test_varargs_macros ();
-
-  // Check flexible array members.
-  struct incomplete_array *ia =
-    malloc (sizeof (struct incomplete_array) + (sizeof (double) * 10));
-  ia->datasize = 10;
-  for (int i = 0; i < ia->datasize; ++i)
-    ia->data[i] = i * 1.234;
-
-  // Check named initializers.
-  struct named_init ni = {
-    .number = 34,
-    .name = L"Test wide string",
-    .average = 543.34343,
-  };
-
-  ni.number = 58;
-
-  int dynamic_array[ni.number];
-  dynamic_array[ni.number - 1] = 543;
-
-  // work around unused variable warnings
-  return (!success || bignum == 0LL || ubignum == 0uLL || newvar[0] == 'x'
-	  || dynamic_array[ni.number - 1] != 543);
-]])

--- a/m4/prog_cxx.m4	Fri Mar 18 13:37:33 2016 -0400
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,329 +0,0 @@
-# Copyright (C) 2001-2016 Free Software Foundation, Inc.
-#
-#
-# This is pretty much copy and paste of the unreleased autoconf macros
-# (where it is named AC_PROG_CC_C11).  Once we are dependent on
-# autoconf version with that macro, we can simply change to use that
-# one instead.  Copied from autoconf commit 04be2b7a (2016/02/06)
-#
-#
-# This file is part of Autoconf.  This program is free
-# software; you can redistribute it and/or modify it under the
-# terms of the GNU General Public License as published by the
-# Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
-#
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, see <http://www.gnu.org/licenses/>.
-
-# OCTAVE_PROG_CXX_CXX11 ([ACTION-IF-AVAILABLE], [ACTION-IF-UNAVAILABLE])
-# -------------------------------------------------------------------
-# If the C++ compiler is not in ISO CXX11 mode by default, try to add
-# an option to output variable CXX to make it so.  This macro tries
-# various options that select ISO C++11 on some system or another.  It
-# considers the compiler to be in ISO C++11 mode if it handles all the
-# tests from the C++98 checks, plus the following: Language features
-# (auto, constexpr, decltype, default/deleted constructors, delegate
-# constructors, final, initialiser lists, lambda functions, nullptr,
-# override, range-based for loops, template brackets without spaces,
-# unicode literals) and library features (array, memory (shared_ptr,
-# weak_ptr), regex and tuple types).
-AC_DEFUN([OCTAVE_PROG_CXX_CXX11],
-[OCTAVE_CXX_STD_TRY([cxx11],
-[OCTAVE_CXX_CXX11_TEST_HEADER
-OCTAVE_CXX_CXX98_TEST_HEADER],
-[OCTAVE_CXX_CXX11_TEST_BODY
-OCTAVE_CXX_CXX98_TEST_BODY],
-dnl Try
-dnl GCC		-std=gnu++11 (unused restrictive mode: -std=c++11) [and 0x variants]
-dnl IBM XL C	-qlanglvl=extended0x
-dnl		(pre-V12.1; unused restrictive mode: -qlanglvl=stdcxx11)
-dnl HP aC++	-AA
-dnl Intel ICC	-std=c++11 -std=c++0x
-dnl Solaris	N/A (no support)
-dnl Tru64	N/A (no support)
-dnl with extended modes being tried first.
-[[-std=gnu++11 -std=c++11 -std=gnu++0x -std=c++0x -qlanglvl=extended0x -AA]], [$1], [$2])[]dnl
-])# OCTAVE_PROG_CXX_CXX11
-
-
-# OCTAVE_CXX_STD_TRY(STANDARD, TEST-PROLOGUE, TEST-BODY, OPTION-LIST,
-#		  ACTION-IF-AVAILABLE, ACTION-IF-UNAVAILABLE)
-# ----------------------------------------------------------------
-# Check whether the C++ compiler accepts features of STANDARD (e.g
-# `cxx98', `cxx11') by trying to compile a program of TEST-PROLOGUE
-# and TEST-BODY.  If this fails, try again with each compiler option
-# in the space-separated OPTION-LIST; if one helps, append it to CXX.
-# If eventually successful, run ACTION-IF-AVAILABLE, else
-# ACTION-IF-UNAVAILABLE.
-AC_DEFUN([OCTAVE_CXX_STD_TRY],
-[AC_MSG_CHECKING([for $CXX option to enable ]m4_translit(m4_translit($1, [x], [+]), [a-z], [A-Z])[ features])
-AC_LANG_PUSH(C++)dnl
-AC_CACHE_VAL(ac_cv_prog_cxx_$1,
-[ac_cv_prog_cxx_$1=no
-ac_save_CXX=$CXX
-AC_LANG_CONFTEST([AC_LANG_PROGRAM([$2], [$3])])
-for ac_arg in '' $4
-do
-  CXX="$ac_save_CXX $ac_arg"
-  _AC_COMPILE_IFELSE([], [ac_cv_prog_cxx_$1=$ac_arg])
-  test "x$ac_cv_prog_cxx_$1" != "xno" && break
-done
-rm -f conftest.$ac_ext
-CXX=$ac_save_CXX
-])# AC_CACHE_VAL
-ac_prog_cxx_stdcxx_options=
-case "x$ac_cv_prog_cxx_$1" in
-  x)
-    AC_MSG_RESULT([none needed]) ;;
-  xno)
-    AC_MSG_RESULT([unsupported]) ;;
-  *)
-    ac_prog_cxx_stdcxx_options=" $ac_cv_prog_cxx_$1"
-    CXX=$CXX$ac_prog_cxx_stdcxx_options
-    AC_MSG_RESULT([$ac_cv_prog_cxx_$1]) ;;
-esac
-AC_LANG_POP(C++)dnl
-AS_IF([test "x$ac_cv_prog_cxx_$1" != xno], [$5], [$6])
-])# OCTAVE_CXX_STD_TRY
-
-# OCTAVE_CXX_CXX98_TEST_HEADER
-# -------------------------
-# A C++ header suitable for testing for CXX98.
-AC_DEFUN([OCTAVE_CXX_CXX98_TEST_HEADER],
-[[
-#include <algorithm>
-#include <cstdlib>
-#include <fstream>
-#include <iomanip>
-#include <iostream>
-#include <list>
-#include <map>
-#include <set>
-#include <sstream>
-#include <stdexcept>
-#include <string>
-#include <utility>
-#include <vector>
-
-namespace test {
-  typedef std::vector<std::string> string_vec;
-  typedef std::pair<int,bool> map_value;
-  typedef std::map<std::string,map_value> map_type;
-  typedef std::set<int> set_type;
-
-  template<typename T>
-  class printer {
-  public:
-    printer(std::ostringstream& os): os(os) {}
-    void operator() (T elem) { os << elem << std::endl; }
-  private:
-    std::ostringstream& os;
-  };
-}
-]])# OCTAVE_CXX_CXX98_TEST_HEADER
-
-# OCTAVE_CXX_CXX98_TEST_BODY
-# -----------------------
-# A C++ body suitable for testing for CXX98, assuming the corresponding header.
-AC_DEFUN([OCTAVE_CXX_CXX98_TEST_BODY],
-[[
-
-try {
-  // Basic string.
-  std::string teststr("ASCII text");
-  teststr += " string";
-
-  // Simple vector.
-  test::string_vec testvec;
-  testvec.push_back(teststr);
-  testvec.push_back("foo");
-  testvec.push_back("bar");
-  if (testvec.size() != 3) {
-    throw std::runtime_error("vector size is not 1");
-  }
-
-  // Dump vector into stringstream and obtain string.
-  std::ostringstream os;
-  for (test::string_vec::const_iterator i = testvec.begin();
-       i != testvec.end(); ++i) {
-    if (i + 1 != testvec.end()) {
-      os << teststr << '\n';
-    }
-  }
-  // Check algorithms work.
-  std::for_each(testvec.begin(), testvec.end(), test::printer<std::string>(os));
-  std::string os_out = os.str();
-
-  // Test pair and map.
-  test::map_type testmap;
-  testmap.insert(std::make_pair(std::string("key"),
-                                std::make_pair(53,false)));
-
-  // Test set.
-  int values[] = {9, 7, 13, 15, 4, 18, 12, 10, 5, 3, 14, 19, 17, 8, 6, 20, 16, 2, 11, 1};
-  test::set_type testset(values, values + sizeof(values)/sizeof(values[0]));
-  std::list<int> testlist(testset.begin(), testset.end());
-  std::copy(testset.begin(), testset.end(), std::back_inserter(testlist));
-} catch (const std::exception& e) {
-  std::cerr << "Caught exception: " << e.what() << std::endl;
-
-  // Test fstream
-  std::ofstream of("test.txt");
-  of << "Test ASCII text\n" << std::flush;
-  of << "N= " << std::hex << std::setw(8) << std::left << 534 << std::endl;
-  of.close();
-}
-std::exit(0);
-]])
-
-
-# OCTAVE_CXX_CXX11_TEST_HEADER
-# -------------------------
-# A C++ header suitable for testing for CXX11.
-AC_DEFUN([OCTAVE_CXX_CXX11_TEST_HEADER],
-[[
-#include <deque>
-#include <functional>
-#include <memory>
-#include <tuple>
-#include <array>
-#include <regex>
-#include <iostream>
-
-namespace cxx11test
-{
-  typedef std::shared_ptr<std::string> sptr;
-  typedef std::weak_ptr<std::string> wptr;
-
-  typedef std::tuple<std::string,int,double> tp;
-  typedef std::array<int, 20> int_array;
-
-  constexpr int get_val() { return 20; }
-
-  struct testinit
-  {
-    int i;
-    double d;
-  };
-
-  class delegate  {
-  public:
-    delegate(int n) : n(n) {}
-    delegate(): delegate(2354) {}
-
-    virtual int getval() { return this->n; };
-  protected:
-    int n;
-  };
-
-  class overridden : public delegate {
-  public:
-    overridden(int n): delegate(n) {}
-    virtual int getval() override final { return this->n * 2; }
-  };
-
-  class nocopy {
-  public:
-    nocopy(int i): i(i) {}
-    nocopy() = default;
-    nocopy(const nocopy&) = delete;
-    nocopy & operator=(const nocopy&) = delete;
-  private:
-    int i;
-  };
-}
-]])# OCTAVE_CXX_CXX11_TEST_HEADER
-
-# OCTAVE_CXX_CXX11_TEST_BODY
-# -----------------------
-# A C++ body suitable for testing for CXX11, assuming the corresponding header.
-AC_DEFUN([OCTAVE_CXX_CXX11_TEST_BODY],
-[[
-{
-  // Test auto and decltype
-  std::deque<int> d;
-  d.push_front(43);
-  d.push_front(484);
-  d.push_front(3);
-  d.push_front(844);
-  int total = 0;
-  for (auto i = d.begin(); i != d.end(); ++i) { total += *i; }
-
-  auto a1 = 6538;
-  auto a2 = 48573953.4;
-  auto a3 = "String literal";
-
-  decltype(a2) a4 = 34895.034;
-}
-{
-  // Test constexpr
-  short sa[cxx11test::get_val()] = { 0 };
-}
-{
-  // Test initialiser lists
-  cxx11test::testinit il = { 4323, 435234.23544 };
-}
-{
-  // Test range-based for and lambda
-  cxx11test::int_array array = {9, 7, 13, 15, 4, 18, 12, 10, 5, 3, 14, 19, 17, 8, 6, 20, 16, 2, 11, 1};
-  for (int &x : array) { x += 23; }
-  std::for_each(array.begin(), array.end(), [](int v1){ std::cout << v1; });
-}
-{
-  using cxx11test::sptr;
-  using cxx11test::wptr;
-
-  sptr sp(new std::string("ASCII string"));
-  wptr wp(sp);
-  sptr sp2(wp);
-}
-{
-  cxx11test::tp tuple("test", 54, 45.53434);
-  double d = std::get<2>(tuple);
-  std::string s;
-  int i;
-  std::tie(s,i,d) = tuple;
-}
-{
-  static std::regex filename_regex("^_?([a-z0-9_.]+-)+[a-z0-9]+$");
-  std::string testmatch("Test if this string matches");
-  bool match = std::regex_search(testmatch, filename_regex);
-}
-{
-  cxx11test::int_array array = {9, 7, 13, 15, 4, 18, 12, 10, 5, 3, 14, 19, 17, 8, 6, 20, 16, 2, 11, 1};
-  cxx11test::int_array::size_type size = array.size();
-}
-{
-  // Test constructor delegation
-  cxx11test::delegate d1;
-  cxx11test::delegate d2();
-  cxx11test::delegate d3(45);
-}
-{
-  // Test override and final
-  cxx11test::overridden o1(55464);
-}
-{
-  // Test nullptr
-  char *c = nullptr;
-}
-{
-  // Test template brackets
-  std::vector<std::pair<int,char*>> v1;
-}
-{
-  // Unicode literals
-  // FIXME: Octave-specific change, this feature test is modified from the
-  // original Autoconf source. The "const" type qualifier is strictly required,
-  // needed for this test to pass with clang for example.
-  const char *utf8 = u8"UTF-8 string \u2500";
-  const char16_t *utf16 = u"UTF-8 string \u2500";
-  const char32_t *utf32 = U"UTF-32 string \u2500";
-}
-]])