Change structure member sType to non-const to allow default assignment operator. Make copy constructor and copy assignment default. The latter is required for C++20 designated initializers. Delegate the constructor from C-type to the copy constructor by casting rhs accordingly. Fix warnings on gcc/clang.

samples/InstanceVersion/InstanceVersion.cpp

@@ -20,9 +20,6 @@
 #include <iostream>
 #include <sstream>
 
-static char const * AppName    = "InstanceVersion";
-static char const * EngineName = "Vulkan.hpp";
-
 std::string decodeAPIVersion( uint32_t apiVersion )
 {
   return std::to_string( VK_VERSION_MAJOR( apiVersion ) ) + "." + std::to_string( VK_VERSION_MINOR( apiVersion ) ) +