In configure, check for C++11
diff --git a/Makefile.in b/Makefile.in
index a0305da..2396714 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -193,6 +193,7 @@
ECHO_N = @ECHO_N@
ECHO_T = @ECHO_T@
EXEEXT = @EXEEXT@
+HAVE_CXX11 = @HAVE_CXX11@
INSTALL = @INSTALL@
INSTALL_DATA = @INSTALL_DATA@
INSTALL_PROGRAM = @INSTALL_PROGRAM@
diff --git a/config.h.in b/config.h.in
index a00cdbb..0843d74 100644
--- a/config.h.in
+++ b/config.h.in
@@ -3,6 +3,9 @@
/* 1 if have the `boost::shared_ptr' class. */
#undef HAVE_BOOST_SHARED_PTR
+/* define if the compiler supports basic C++11 syntax */
+#undef HAVE_CXX11
+
/* 1 if have the `std::shared_ptr' class. */
#undef HAVE_STD_SHARED_PTR
diff --git a/configure b/configure
index 90c59fb..fa1b828 100755
--- a/configure
+++ b/configure
@@ -585,6 +585,7 @@
am__EXEEXT_TRUE
LTLIBOBJS
LIBOBJS
+HAVE_CXX11
am__fastdepCXX_FALSE
am__fastdepCXX_TRUE
CXXDEPMODE
@@ -3048,9 +3049,179 @@
ac_compiler_gnu=$ac_cv_cxx_compiler_gnu
+ ax_cxx_compile_cxx11_required=falsednl
+ ac_ext=cpp
+ac_cpp='$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");
+ };
+
+ 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;
+
+_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$ac_success = xno; then
+ for switch in -std=gnu++11 -std=gnu++0x; do
+ cachevar=`$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");
+ };
+
+ 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;
+
+_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 $switch"
+ ac_success=yes
+ break
+ fi
+ done
+ fi
+
+ if test x$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");
+ };
+
+ 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;
+
+_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
+
+
{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for std::shared_ptr" >&5
$as_echo_n "checking for std::shared_ptr... " >&6; }
-
cat confdefs.h - <<_ACEOF >conftest.$ac_ext
/* end confdefs.h. */
#include <memory>
diff --git a/configure.ac b/configure.ac
index af7095e..27b0154 100644
--- a/configure.ac
+++ b/configure.ac
@@ -6,6 +6,7 @@
AC_CONFIG_HEADERS([config.h])
AC_PROG_CXX
AC_LANG([C++])
+AX_CXX_COMPILE_STDCXX_11(, optional)
AC_MSG_CHECKING([for std::shared_ptr])
AC_COMPILE_IFELSE([AC_LANG_PROGRAM(