Build: Enable and require c++17

cmake/macros/ConfigureBaseTargets.cmake

@@ -19,6 +19,7 @@ add_library(trinity-feature-interface INTERFACE)
 
 target_compile_features(trinity-feature-interface
   INTERFACE
+    cxx_std_17
     cxx_alias_templates
     cxx_auto_type
     cxx_constexpr

cmake/macros/FindPCHSupport.cmake

@@ -20,7 +20,7 @@ function(ADD_CXX_PCH TARGET_NAME_LIST PCH_HEADER)
     set_target_properties(${TARGET_NAME} PROPERTIES COTIRE_CXX_PREFIX_HEADER_INIT ${PCH_HEADER})
 
     # Workaround for cotire bug: https://github.com/sakra/cotire/issues/138
-    set_property(TARGET ${TARGET_NAME} PROPERTY CXX_STANDARD 14)
+    set_property(TARGET ${TARGET_NAME} PROPERTY CXX_STANDARD 17)
   endforeach()
 
   cotire(${TARGET_NAME_LIST})