Merge pull request #1391 from delcypher/cxx_example_use_cxx11

[CMake] Use C++11 is C++ API example

RELEASE_NOTES

@@ -1,7 +1,11 @@
 RELEASE NOTES
 
-Version 4.5.x
+Version 4.6.0
 =============
+- New requirements:
+  - C++11 capable compiler to build Z3.
+  - C++ API now requires C++11 or newer.
+
 - New features (including):
   - A new string solver from University of Waterloo
   - A new linear real arithmetic solver

examples/c++/CMakeLists.txt

@@ -13,6 +13,22 @@ find_package(Z3
   # use this option.
   NO_DEFAULT_PATH
 )
+
+################################################################################
+# Z3 C++ API bindings require C++11
+################################################################################
+if ("${CMAKE_VERSION}" VERSION_LESS "3.1")
+  # Legacy CMake support
+  if (("${CMAKE_CXX_COMPILER_ID}" MATCHES "GNU") OR ("${CMAKE_CXX_COMPILER_ID}" MATCHES "Clang"))
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
+  else()
+    message(FATAL_ERROR "Setting C++ version to C++11 not supported for \"${CMAKE_CXX_COMPILER_ID}\"")
+  endif()
+else ()
+  set(CMAKE_CXX_STANDARD 11)
+  set(CMAKE_CXX_STANDARD_REQUIRED ON)
+endif ()
+
 message(STATUS "Z3_FOUND: ${Z3_FOUND}")
 message(STATUS "Found Z3 ${Z3_VERSION_STRING}")
 message(STATUS "Z3_DIR: ${Z3_DIR}")