Require C++17 (#2356)

This enables many useful newer C++ features. C++17 is already required
by many components of the Khronos ecosystem.

Signed-off-by: Kevin Petit <[email protected]>

Author: kpet

CMakeLists.txt

@@ -7,7 +7,7 @@ project(CLConform${CONFORMANCE_SUFFIX})
 
 set(CMAKE_C_STANDARD 99)
 set(CMAKE_C_STANDARD_REQUIRED ON)
-set(CMAKE_CXX_STANDARD 11)
+set(CMAKE_CXX_STANDARD 17)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 
 add_definitions(-DCL_TARGET_OPENCL_VERSION=300)