Vulkan: Default construct slang_reflection instead.

We will use non-POD when dealing with user-defined inputs.

gfx/drivers_shader/shader_vulkan.cpp

@@ -981,7 +981,7 @@ bool Pass::build()
                pass_info.rt_format));
    }
 
-   memset(&reflection, 0, sizeof(reflection));
+   reflection = slang_reflection{};
    if (!slang_reflect_spirv(vertex_shader, fragment_shader, &reflection))
       return false;
 

gfx/drivers_shader/slang_reflection.hpp

@@ -60,6 +60,8 @@ struct slang_semantic_meta
 
 struct slang_reflection
 {
+   slang_reflection() = default;
+
    size_t ubo_size = 0;
    unsigned ubo_binding = 0;
    uint32_t ubo_stage_mask = 0;