casa-mp-base

diff --git a/configure.ac b/configure.ac

index 90c042e..b5bf97a 100644

--- a/configure.ac

+++ b/configure.ac

@@ -92,7 +92,15 @@

     AX_CHECK_COMPILE_FLAG([-Wc++98-compat -Wc++98-compat-pedantic], [CXXFLAGS+=" -Wc++98-compat"], [])

     AC_LANG_POP([C++])

 else

-    AX_CXX_COMPILE_STDCXX_11([ext], [optional])

+    AC_ARG_ENABLE([cxx11],

+        [AS_HELP_STRING([--enable-cxx11],

+            [enable C++11 for C++ compiler [default=no]])],

+        [zmq_enable_cxx11=$enableval],

+        [zmq_enable_cxx11="no"])

+    if test "x$zmq_enable_cxx11" != "xno"; then

+        AX_CXX_COMPILE_STDCXX_11([ext], [mandatory])

+        AC_DEFINE(ZMQ_USE_CXX11, 1, [Enable C++11])

+    fi

 fi

 # Check whether to build a with debug symbols

diff --git a/perf/benchmark_radix_tree.cpp b/perf/benchmark_radix_tree.cpp

index efc889c..4cfd4e8 100644

--- a/perf/benchmark_radix_tree.cpp

+++ b/perf/benchmark_radix_tree.cpp

@@ -27,7 +27,7 @@

     along with this program.  If not, see <http://www.gnu.org/licenses/>.

 */

-#if __cplusplus >= 201103L

+#if defined(ZMQ_USE_CXX11)

 #include "radix_tree.hpp"

 #include "trie.hpp"

diff --git a/src/atomic_counter.hpp b/src/atomic_counter.hpp

index 3f62f6f..e1c9600 100644

--- a/src/atomic_counter.hpp

+++ b/src/atomic_counter.hpp

@@ -35,7 +35,7 @@

 #if defined ZMQ_FORCE_MUTEXES

 #define ZMQ_ATOMIC_COUNTER_MUTEX

-#elif (defined __cplusplus && __cplusplus >= 201103L)                          \

+#elif defined(ZMQ_USE_CXX11)                                                   \

   || (defined _MSC_VER && _MSC_VER >= 1900)

 #define ZMQ_ATOMIC_COUNTER_CXX11

 #elif defined ZMQ_HAVE_ATOMIC_INTRINSICS

diff --git a/src/atomic_ptr.hpp b/src/atomic_ptr.hpp

index 7b34500..e85c9f8 100644

--- a/src/atomic_ptr.hpp

+++ b/src/atomic_ptr.hpp

@@ -34,7 +34,7 @@

 #if defined ZMQ_FORCE_MUTEXES

 #define ZMQ_ATOMIC_PTR_MUTEX

-#elif (defined __cplusplus && __cplusplus >= 201103L)                          \

+#elif defined(ZMQ_USE_CXX11)                                                   \

   || (defined _MSC_VER && _MSC_VER >= 1900)

 #define ZMQ_ATOMIC_PTR_CXX11

 #elif defined ZMQ_HAVE_ATOMIC_INTRINSICS

diff --git a/src/blob.hpp b/src/blob.hpp

index c14633c..66a5171 100644

--- a/src/blob.hpp