--- a/build/autoconf/toolchain.m4
+++ b/build/autoconf/toolchain.m4
@@ -220,16 +220,28 @@ if test "$GNU_CXX"; then
 
         if test "ac_cv_cxx0x_clang_workaround" = "no"; then
             AC_MSG_ERROR([Your toolchain does not support C++0x/C++11 mode properly. Please upgrade your toolchain])
         fi
     elif test "$ac_cv_cxx0x_headers_bug" = "yes"; then
         AC_MSG_ERROR([Your toolchain does not support C++0x/C++11 mode properly. Please upgrade your toolchain])
     fi
 
+    if test -n "$CLANG_CC"; then
+        dnl We'd normally just check for the version from CC_VERSION (fed
+        dnl from __clang_major__ and __clang_minor__), but the clang that
+        dnl comes with Xcode has a completely different version scheme
+        dnl despite exposing the version with the same defines.
+        dnl So instead of a version check, check for one of the C++11
+        dnl features that was added in clang 3.3.
+        AC_TRY_COMPILE([], [#if !__has_feature(cxx_inheriting_constructors)
+                            #error inheriting constructors are not supported
+                            #endif],,AC_MSG_ERROR([Only clang/llvm 3.3 or newer supported]))
+    fi
+
     AC_CACHE_CHECK([whether 64-bits std::atomic requires -latomic],
         ac_cv_needs_atomic,
         AC_TRY_LINK(
             [#include <cstdint>
              #include <atomic>],
             [ std::atomic<uint64_t> foo; foo = 1; ],
             ac_cv_needs_atomic=no,
             _SAVE_LIBS="$LIBS"
@@ -316,16 +328,22 @@ EOF
 
             if test "ac_cv_host_cxx0x_clang_workaround" = "no"; then
                 AC_MSG_ERROR([Your host toolchain does not support C++0x/C++11 mode properly. Please upgrade your toolchain])
             fi
             HOST_CXXFLAGS="$CXXFLAGS"
         elif test "$ac_cv_host_cxx0x_headers_bug" = "yes"; then
             AC_MSG_ERROR([Your host toolchain does not support C++0x/C++11 mode properly. Please upgrade your toolchain])
         fi
+        if test "$host_compiler" = CLANG; then
+            AC_TRY_COMPILE([], [#if !__has_feature(cxx_inheriting_constructors)
+                                #error inheriting constructors are not supported
+                                #endif],,AC_MSG_ERROR([Only clang/llvm 3.3 or newer supported]))
+        fi
+
         CXXFLAGS="$_SAVE_CXXFLAGS"
         CPPFLAGS="$_SAVE_CPPFLAGS"
         CXX="$_SAVE_CXX"
     fi
 elif test "$GNU_CXX"; then
     HOST_CXXFLAGS="$HOST_CXXFLAGS $_ADDED_CXXFLAGS"
 fi
 AC_LANG_C