CI errors in [serialization] windows cygwin, mingw builds

From: Jeff Garland (azswdude_at_[hidden])
Date: 2020-07-09 15:06:30

I've been seeing a bunch of CI errors related to serialization that seem to
be new.  Not seeing this so much on the test dashboard however.

https://ci.appveyor.com/project/jeking3/date-time-1evbf/builds/33988388

gcc.compile.c++
bin.v2\libs\serialization\build\gcc-mngw6\rls\cxstd-11-iso\thrd-mlt\vsblt-hdn\xml_iarchive.o
gcc.compile.c++
bin.v2\libs\serialization\build\gcc-mngw6\rls\cxstd-11-iso\thrd-mlt\vsblt-hdn\xml_oarchive.o
In file included from ./boost/archive/iterators/mb_from_wchar.hpp:31,
from ./boost/archive/impl/xml_oarchive_impl.ipp:28,
from libs\serialization\src\xml_oarchive.cpp:23:
./boost/archive/detail/utf8_codecvt_facet.hpp:20: warning:
"BOOST_ARCHIVE_DECL" redefined
20 | #define BOOST_ARCHIVE_DECL
|
In file included from ./boost/archive/detail/auto_link_archive.hpp:26,
from ./boost/archive/xml_oarchive.hpp:29,
from libs\serialization\src\xml_oarchive.cpp:17:
./boost/archive/detail/decl.hpp:28: note: this is the location of the
previous definition
28 | #define BOOST_ARCHIVE_DECL BOOST_SYMBOL_EXPORT
|
gcc.compile.c++
bin.v2\libs\serialization\build\gcc-mngw6\rls\cxstd-11-iso\thrd-mlt\vsblt-hdn\xml_archive_exception.o
gcc.compile.c++ bin.v2\libs\serialization\build\gcc-mngw6\rls\cxs