# HG changeset patch
# User Chris Cannam
# Date 1416238267 0
# Node ID dbb7f0ab011e7cc6f634e9623b956bf50174caad
# Parent  36f79bc5c3d751409e3075df278168c5d7880f71
CXX11 (-std=c++11) branch, to test build environments before making any code adaptations

diff -r 36f79bc5c3d7 -r dbb7f0ab011e acinclude.m4
--- a/acinclude.m4	Fri Nov 14 17:23:38 2014 +0000
+++ b/acinclude.m4	Mon Nov 17 15:31:07 2014 +0000
@@ -112,3 +112,146 @@
 
 ])
 
+# From autoconf archive:
+
+# ============================================================================
+#  http://www.gnu.org/software/autoconf-archive/ax_cxx_compile_stdcxx_11.html
+# ============================================================================
+#
+# SYNOPSIS
+#
+#   AX_CXX_COMPILE_STDCXX_11([ext|noext],[mandatory|optional])
+#
+# DESCRIPTION
+#
+#   Check for baseline language coverage in the compiler for the C++11
+#   standard; if necessary, add switches to CXXFLAGS to enable support.
+#
+#   The first argument, if specified, indicates whether you insist on an
+#   extended mode (e.g. -std=gnu++11) or a strict conformance mode (e.g.
+#   -std=c++11).  If neither is specified, you get whatever works, with
+#   preference for an extended mode.
+#
+#   The second argument, if specified 'mandatory' or if left unspecified,
+#   indicates that baseline C++11 support is required and that the macro
+#   should error out if no mode with that support is found.  If specified
+#   'optional', then configuration proceeds regardless, after defining
+#   HAVE_CXX11 if and only if a supporting mode is found.
+#
+# LICENSE
+#
+#   Copyright (c) 2008 Benjamin Kosnik <bkoz@redhat.com>
+#   Copyright (c) 2012 Zack Weinberg <zackw@panix.com>
+#   Copyright (c) 2013 Roy Stogner <roystgnr@ices.utexas.edu>
+#   Copyright (c) 2014 Alexey Sokolov <sokolov@google.com>
+#
+#   Copying and distribution of this file, with or without modification, are
+#   permitted in any medium without royalty provided the copyright notice
+#   and this notice are preserved. This file is offered as-is, without any
+#   warranty.
+
+m4_define([_AX_CXX_COMPILE_STDCXX_11_testbody], [[
+  template <typename T>
+    struct check
+    {
+      static_assert(sizeof(int) <= sizeof(T), "not big enough");
+    };
+
+    struct Base {
+    virtual void f() {}
+    };
+    struct Child : public Base {
+    virtual void f() override {}
+    };
+
+    typedef check<check<bool>> right_angle_brackets;
+
+    int a;
+    decltype(a) b;
+
+    typedef check<int> check_type;
+    check_type c;
+    check_type&& cr = static_cast<check_type&&>(c);
+
+    auto d = a;
+    auto l = [](){};
+]])
+
+AC_DEFUN([AX_CXX_COMPILE_STDCXX_11], [dnl
+  m4_if([$1], [], [],
+        [$1], [ext], [],
+        [$1], [noext], [],
+        [m4_fatal([invalid argument `$1' to AX_CXX_COMPILE_STDCXX_11])])dnl
+  m4_if([$2], [], [ax_cxx_compile_cxx11_required=true],
+        [$2], [mandatory], [ax_cxx_compile_cxx11_required=true],
+        [$2], [optional], [ax_cxx_compile_cxx11_required=false],
+        [m4_fatal([invalid second argument `$2' to AX_CXX_COMPILE_STDCXX_11])])
+  AC_LANG_PUSH([C++])dnl
+  ac_success=no
+  AC_CACHE_CHECK(whether $CXX supports C++11 features by default,
+  ax_cv_cxx_compile_cxx11,
+  [AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_11_testbody])],
+    [ax_cv_cxx_compile_cxx11=yes],
+    [ax_cv_cxx_compile_cxx11=no])])
+  if test x$ax_cv_cxx_compile_cxx11 = xyes; then
+    ac_success=yes
+  fi
+
+  m4_if([$1], [noext], [], [dnl
+  if test x$ac_success = xno; then
+    for switch in -std=gnu++11 -std=gnu++0x; do
+      cachevar=AS_TR_SH([ax_cv_cxx_compile_cxx11_$switch])
+      AC_CACHE_CHECK(whether $CXX supports C++11 features with $switch,
+                     $cachevar,
+        [ac_save_CXXFLAGS="$CXXFLAGS"
+         CXXFLAGS="$CXXFLAGS $switch"
+         AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_11_testbody])],
+          [eval $cachevar=yes],
+          [eval $cachevar=no])
+         CXXFLAGS="$ac_save_CXXFLAGS"])
+      if eval test x\$$cachevar = xyes; then
+        CXXFLAGS="$CXXFLAGS $switch"
+        ac_success=yes
+        break
+      fi
+    done
+  fi])
+
+  m4_if([$1], [ext], [], [dnl
+  if test x$ac_success = xno; then
+    for switch in -std=c++11 -std=c++0x; do
+      cachevar=AS_TR_SH([ax_cv_cxx_compile_cxx11_$switch])
+      AC_CACHE_CHECK(whether $CXX supports C++11 features with $switch,
+                     $cachevar,
+        [ac_save_CXXFLAGS="$CXXFLAGS"
+         CXXFLAGS="$CXXFLAGS $switch"
+         AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_11_testbody])],
+          [eval $cachevar=yes],
+          [eval $cachevar=no])
+         CXXFLAGS="$ac_save_CXXFLAGS"])
+      if eval test x\$$cachevar = xyes; then
+        CXXFLAGS="$CXXFLAGS $switch"
+        ac_success=yes
+        break
+      fi
+    done
+  fi])
+  AC_LANG_POP([C++])
+  if test x$ax_cxx_compile_cxx11_required = xtrue; then
+    if test x$ac_success = xno; then
+      AC_MSG_ERROR([*** A compiler with support for C++11 language features is required.])
+    fi
+  else
+    if test x$ac_success = xno; then
+      HAVE_CXX11=0
+      AC_MSG_NOTICE([No compiler with C++11 support was found])
+    else
+      HAVE_CXX11=1
+      AC_DEFINE(HAVE_CXX11,1,
+                [define if the compiler supports basic C++11 syntax])
+    fi
+
+    AC_SUBST(HAVE_CXX11)
+  fi
+])
+
diff -r 36f79bc5c3d7 -r dbb7f0ab011e configure
--- a/configure	Fri Nov 14 17:23:38 2014 +0000
+++ b/configure	Mon Nov 17 15:31:07 2014 +0000
@@ -673,6 +673,7 @@
 EGREP
 GREP
 CXXCPP
+HAVE_CXX11
 MKDIR_P
 INSTALL_DATA
 INSTALL_SCRIPT
@@ -3449,6 +3450,146 @@
 $as_echo "$MKDIR_P" >&6; }
 
 
+# We are daringly making use of C++11 now
+
+    ax_cxx_compile_cxx11_required=true
+  ac_ext=cpp
+ac_cpp='$CXXCPP $CPPFLAGS'
+ac_compile='$CXX -c $CXXFLAGS $CPPFLAGS conftest.$ac_ext >&5'
+ac_link='$CXX -o conftest$ac_exeext $CXXFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
+ac_compiler_gnu=$ac_cv_cxx_compiler_gnu
+  ac_success=no
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CXX supports C++11 features by default" >&5
+$as_echo_n "checking whether $CXX supports C++11 features by default... " >&6; }
+if ${ax_cv_cxx_compile_cxx11+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+  template <typename T>
+    struct check
+    {
+      static_assert(sizeof(int) <= sizeof(T), "not big enough");
+    };
+
+    struct Base {
+    virtual void f() {}
+    };
+    struct Child : public Base {
+    virtual void f() override {}
+    };
+
+    typedef check<check<bool>> right_angle_brackets;
+
+    int a;
+    decltype(a) b;
+
+    typedef check<int> check_type;
+    check_type c;
+    check_type&& cr = static_cast<check_type&&>(c);
+
+    auto d = a;
+    auto l = [](){};
+
+_ACEOF
+if ac_fn_cxx_try_compile "$LINENO"; then :
+  ax_cv_cxx_compile_cxx11=yes
+else
+  ax_cv_cxx_compile_cxx11=no
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ax_cv_cxx_compile_cxx11" >&5
+$as_echo "$ax_cv_cxx_compile_cxx11" >&6; }
+  if test x$ax_cv_cxx_compile_cxx11 = xyes; then
+    ac_success=yes
+  fi
+
+
+
+    if test x$ac_success = xno; then
+    for switch in -std=c++11 -std=c++0x; do
+      cachevar=`$as_echo "ax_cv_cxx_compile_cxx11_$switch" | $as_tr_sh`
+      { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CXX supports C++11 features with $switch" >&5
+$as_echo_n "checking whether $CXX supports C++11 features with $switch... " >&6; }
+if eval \${$cachevar+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  ac_save_CXXFLAGS="$CXXFLAGS"
+         CXXFLAGS="$CXXFLAGS $switch"
+         cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+  template <typename T>
+    struct check
+    {
+      static_assert(sizeof(int) <= sizeof(T), "not big enough");
+    };
+
+    struct Base {
+    virtual void f() {}
+    };
+    struct Child : public Base {
+    virtual void f() override {}
+    };
+
+    typedef check<check<bool>> right_angle_brackets;
+
+    int a;
+    decltype(a) b;
+
+    typedef check<int> check_type;
+    check_type c;
+    check_type&& cr = static_cast<check_type&&>(c);
+
+    auto d = a;
+    auto l = [](){};
+
+_ACEOF
+if ac_fn_cxx_try_compile "$LINENO"; then :
+  eval $cachevar=yes
+else
+  eval $cachevar=no
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+         CXXFLAGS="$ac_save_CXXFLAGS"
+fi
+eval ac_res=\$$cachevar
+	       { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_res" >&5
+$as_echo "$ac_res" >&6; }
+      if eval test x\$$cachevar = xyes; then
+        CXXFLAGS="$CXXFLAGS $switch"
+        ac_success=yes
+        break
+      fi
+    done
+  fi
+  ac_ext=cpp
+ac_cpp='$CXXCPP $CPPFLAGS'
+ac_compile='$CXX -c $CXXFLAGS $CPPFLAGS conftest.$ac_ext >&5'
+ac_link='$CXX -o conftest$ac_exeext $CXXFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
+ac_compiler_gnu=$ac_cv_cxx_compiler_gnu
+
+  if test x$ax_cxx_compile_cxx11_required = xtrue; then
+    if test x$ac_success = xno; then
+      as_fn_error $? "*** A compiler with support for C++11 language features is required." "$LINENO" 5
+    fi
+  else
+    if test x$ac_success = xno; then
+      HAVE_CXX11=0
+      { $as_echo "$as_me:${as_lineno-$LINENO}: No compiler with C++11 support was found" >&5
+$as_echo "$as_me: No compiler with C++11 support was found" >&6;}
+    else
+      HAVE_CXX11=1
+
+$as_echo "#define HAVE_CXX11 1" >>confdefs.h
+
+    fi
+
+
+  fi
+
 
 ac_ext=cpp
 ac_cpp='$CXXCPP $CPPFLAGS'
@@ -4202,9 +4343,9 @@
 CXXFLAGS_MINIMAL="$AUTOCONF_CXXFLAGS"
 
 if test "x$GCC" = "xyes"; then
-        CXXFLAGS_DEBUG="-Wall -Wextra -Werror -Woverloaded-virtual -Wformat-nonliteral -Wformat-security -Winit-self -Wswitch-enum -g -pipe"
-   	CXXFLAGS_RELEASE="-g0 -O2 -Wall -pipe"
-   	CXXFLAGS_MINIMAL="-g0 -O0"
+        CXXFLAGS_DEBUG="-std=c++11 -Wall -Wextra -Werror -Woverloaded-virtual -Wformat-nonliteral -Wformat-security -Winit-self -Wswitch-enum -g -pipe"
+   	CXXFLAGS_RELEASE="-std=c++11 -g0 -O2 -Wall -pipe"
+   	CXXFLAGS_MINIMAL="-std=c++11 -g0 -O0"
 fi
 
 CXXFLAGS_BUILD="$CXXFLAGS_RELEASE"
diff -r 36f79bc5c3d7 -r dbb7f0ab011e configure.ac
--- a/configure.ac	Fri Nov 14 17:23:38 2014 +0000
+++ b/configure.ac	Mon Nov 17 15:31:07 2014 +0000
@@ -25,6 +25,9 @@
 AC_PROG_INSTALL
 AC_PROG_MKDIR_P
 
+# We are daringly making use of C++11 now
+AX_CXX_COMPILE_STDCXX_11(noext)
+
 AC_HEADER_STDC
 
 # These are the flags Autoconf guesses for us; we use them later if
@@ -50,9 +53,9 @@
 CXXFLAGS_MINIMAL="$AUTOCONF_CXXFLAGS"
 
 if test "x$GCC" = "xyes"; then
-        CXXFLAGS_DEBUG="-Wall -Wextra -Werror -Woverloaded-virtual -Wformat-nonliteral -Wformat-security -Winit-self -Wswitch-enum -g -pipe"
-   	CXXFLAGS_RELEASE="-g0 -O2 -Wall -pipe"
-   	CXXFLAGS_MINIMAL="-g0 -O0"
+        CXXFLAGS_DEBUG="-std=c++11 -Wall -Wextra -Werror -Woverloaded-virtual -Wformat-nonliteral -Wformat-security -Winit-self -Wswitch-enum -g -pipe"
+   	CXXFLAGS_RELEASE="-std=c++11 -g0 -O2 -Wall -pipe"
+   	CXXFLAGS_MINIMAL="-std=c++11 -g0 -O0"
 fi
 
 CXXFLAGS_BUILD="$CXXFLAGS_RELEASE"