Build for Lua 5.3 only

Other “lua_single_target” USE_EXPAND flag values

Use FlagDescription
lua_single_target_lua5-1Build for Lua 5.1 only
lua_single_target_lua5-3Build for Lua 5.3 only
lua_single_target_lua5-4Build for Lua 5.4 only
lua_single_target_luajitBuild for LuaJIT only

All packages providing a “lua_single_target_lua5-3” USE flag (66)