configure.ac: require C++11 compiler

We'll add some C++11 code soon.

1 files changed, 107 insertions, 0 deletions

diff --git a/m4/ax_cxx_compile_stdcxx_0x.m4 b/m4/ax_cxx_compile_stdcxx_0x.m4
new file mode 100644
index 000000000..a4e556ff9
--- /dev/null
+++ b/m4/ax_cxx_compile_stdcxx_0x.m4
@@ -0,0 +1,107 @@
+# ============================================================================
+#  http://www.gnu.org/software/autoconf-archive/ax_cxx_compile_stdcxx_0x.html
+# ============================================================================
+#
+# SYNOPSIS
+#
+#   AX_CXX_COMPILE_STDCXX_0X
+#
+# DESCRIPTION
+#
+#   Check for baseline language coverage in the compiler for the C++0x
+#   standard.
+#
+# LICENSE
+#
+#   Copyright (c) 2008 Benjamin Kosnik <bkoz@redhat.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.
+
+#serial 7
+
+AU_ALIAS([AC_CXX_COMPILE_STDCXX_0X], [AX_CXX_COMPILE_STDCXX_0X])
+AC_DEFUN([AX_CXX_COMPILE_STDCXX_0X], [
+  AC_CACHE_CHECK(if g++ supports C++0x features without additional flags,
+  ax_cv_cxx_compile_cxx0x_native,
+  [AC_LANG_SAVE
+  AC_LANG_CPLUSPLUS
+  AC_TRY_COMPILE([
+  template <typename T>
+    struct check
+    {
+      static_assert(sizeof(int) <= sizeof(T), "not big enough");
+    };
+
+    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);],,
+  ax_cv_cxx_compile_cxx0x_native=yes, ax_cv_cxx_compile_cxx0x_native=no)
+  AC_LANG_RESTORE
+  ])
+
+  AC_CACHE_CHECK(if g++ supports C++0x features with -std=c++0x,
+  ax_cv_cxx_compile_cxx0x_cxx,
+  [AC_LANG_SAVE
+  AC_LANG_CPLUSPLUS
+  ac_save_CXXFLAGS="$CXXFLAGS"
+  CXXFLAGS="$CXXFLAGS -std=c++0x"
+  AC_TRY_COMPILE([
+  template <typename T>
+    struct check
+    {
+      static_assert(sizeof(int) <= sizeof(T), "not big enough");
+    };
+
+    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);],,
+  ax_cv_cxx_compile_cxx0x_cxx=yes, ax_cv_cxx_compile_cxx0x_cxx=no)
+  CXXFLAGS="$ac_save_CXXFLAGS"
+  AC_LANG_RESTORE
+  ])
+
+  AC_CACHE_CHECK(if g++ supports C++0x features with -std=gnu++0x,
+  ax_cv_cxx_compile_cxx0x_gxx,
+  [AC_LANG_SAVE
+  AC_LANG_CPLUSPLUS
+  ac_save_CXXFLAGS="$CXXFLAGS"
+  CXXFLAGS="$CXXFLAGS -std=gnu++0x"
+  AC_TRY_COMPILE([
+  template <typename T>
+    struct check
+    {
+      static_assert(sizeof(int) <= sizeof(T), "not big enough");
+    };
+
+    typedef check<check<bool>> right_angle_brackets;
+
+    int a;
+    decltype(a) b;
+
+    typedef check<int> check_type;
+    check_type c;
+    check_type&& cr = static_cast<check_type&&>(c);],,
+  ax_cv_cxx_compile_cxx0x_gxx=yes, ax_cv_cxx_compile_cxx0x_gxx=no)
+  CXXFLAGS="$ac_save_CXXFLAGS"
+  AC_LANG_RESTORE
+  ])
+
+  if test "$ax_cv_cxx_compile_cxx0x_native" = yes ||
+     test "$ax_cv_cxx_compile_cxx0x_cxx" = yes ||
+     test "$ax_cv_cxx_compile_cxx0x_gxx" = yes; then
+    AC_DEFINE(HAVE_STDCXX_0X,,[Define if g++ supports C++0x features. ])
+  fi
+])