Remove unnecessary C++11 selection code.

Looks like a leftover from the example CMake-file we were
looking at initially.

With or without this part, the generated Makefiles look exactly
the same.

Signed-off-by: Henner Zeller <h.zeller@acm.org>

CMakeLists.txt

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 708b8b6..e567586 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -57,32 +57,6 @@
 set(CMAKE_CXX_FLAGS_DEBUG  "${CMAKE_CXX_FLAGS_DEBUG} -fno-builtin-malloc -fno-builtin-calloc -fno-builtin-realloc -fno-builtin-free -O0 -g ${MY_CXX_WARNING_FLAGS}")
 set(CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} -fno-builtin-malloc -fno-builtin-calloc -fno-builtin-realloc -fno-builtin-free -O3 -DNDEBUG ${MY_CXX_WARNING_FLAGS}")
 
-# Compiler-specific C++11 activation.
-if ("${CMAKE_CXX_COMPILER_ID}" MATCHES "GNU" OR "${CMAKE_CXX_COMPILER_ID}" MATCHES "Intel")
-    execute_process(
-        COMMAND ${CMAKE_CXX_COMPILER} -dumpversion OUTPUT_VARIABLE GCC_VERSION)
-    # Just g++-5.0 and greater contain <codecvt> header. (test in ubuntu)
-    if (NOT (GCC_VERSION VERSION_GREATER 5.0 OR GCC_VERSION VERSION_EQUAL 5.0))
-        message(FATAL_ERROR "${PROJECT_NAME} requires g++ 5.0 or greater.")
-    endif ()
-elseif ("${CMAKE_CXX_COMPILER_ID}" MATCHES "Clang" AND APPLE)
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -stdlib=libc++")
-elseif ("${CMAKE_CXX_COMPILER_ID}" MATCHES "Clang" AND CMAKE_SYSTEM_NAME MATCHES "Linux")
-    execute_process(
-        COMMAND ${CMAKE_CXX_COMPILER} -dumpversion OUTPUT_VARIABLE CLANG_VERSION)
-    if (NOT (CLANG_VERSION VERSION_GREATER 4.2.1 OR CLANG_VERSION VERSION_EQUAL 4.2.1))
-        message(FATAL_ERROR "${PROJECT_NAME} requires clang 4.2.1 or greater.")
-    endif ()
-    # You can use libc++ to compile this project when g++ is NOT greater than or equal to 5.0.
-    if (WITH_LIBCXX)
-        set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -stdlib=libc++")
-    endif()
-elseif ( MSVC_VERSION GREATER 1800 OR MSVC_VERSION EQUAL 1800 )
-  # Visual Studio 2012+ supports c++11 features
-else ()
-    message(FATAL_ERROR "Your C++ compiler does not support C++11.")
-endif ()
-
 # Flatbuffer
 set(flatbuffer-GENERATED_SRC
   ${PROJECT_SOURCE_DIR}/src/Cache/header_generated.h