bump required cmake to 3.1, use CMAKE_CXX_STANDARD to require C++-11

CMakeLists.txt

@@ -1,4 +1,5 @@
-cmake_minimum_required (VERSION 2.8)
+cmake_minimum_required (VERSION 3.1)
+set(CMAKE_CXX_STANDARD 11)
 
 project (qlever-petrimaps)
 
@@ -44,22 +45,6 @@ set(CMAKE_CXX_FLAGS_RELWITHDEBINFO "${CMAKE_CXX_FLAGS} -g -DLOGLEVEL=3")
 # export compile commands to tools like clang
 set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
 
-# Compiler-specific C++11 activation.
-if ("${CMAKE_CXX_COMPILER_ID}" MATCHES "GNU")
-	execute_process(
-		COMMAND ${CMAKE_CXX_COMPILER} -dumpversion OUTPUT_VARIABLE GCC_VERSION)
-	if ((GCC_VERSION VERSION_GREATER 4.8 OR GCC_VERSION VERSION_EQUAL 4.8))
-		set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
-	else ()
-		message(FATAL_ERROR "${PROJECT_NAME} requires g++ 4.8 or greater!")
-	endif ()
-elseif ("${CMAKE_CXX_COMPILER_ID}" MATCHES "Clang")
-	#set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -stdlib=libc++ -std=c++11")
-	set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
-else ()
-	message(FATAL_ERROR "Your C++ compiler does not support C++11.")
-endif ()
-
 set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
 
 # http://brianmilco.blogspot.de/2012/11/cmake-automatically-use-git-tags-as.html