[boost] Suspicious changes to Serialization

The current Serialization emits the following warning: c:\projects\boost-root\boost\serialization\extended_type_info_typeid.hpp(118) : warning C4700: uninitialized local variable 'ap' used which looks legitimate and is caused by the removal of `va_start(ap, count);` in this commit https://github.com/boostorg/serialization/commit/2805bc3faa8f8fb7ce80ec51815... This looks like a mistake to me, and is probably going to cause problems.