Macro rendy::core::hal::spec_const_list

macro_rules! spec_const_list {
    (@ $ (,) ?) => { ... };
    (@ $ head_id : expr => $ head_constant : expr $
 (, $ tail_id : expr => $ tail_constant : expr) * $ (,) ?) => { ... };
    ($ ($ id : expr => $ constant : expr), * $ (,) ?) => { ... };
    ($ ($ constant : expr), * $ (,) ?) => { ... };
}

Macro for specifying list of specialization constatns for EntryPoint.