This was a bug we inherited from BTC which causes some dependencies to
be built without optimization essentially replacing -O2 -pipe with
-O0 because cxxflags is assigned to instead of appended to.
We no longer have zeromq so for us this fixes the fact that bdb is being
compiled without optimization.
https://github.com/bitcoin/bitcoin/pull/22840
bdb 6.X was released under the AGPL, which is incompatible with MIT-licensed
software (the result must be licensed under AGPL). bdb 5.X uses the same license
as bdb 4.8, and thus retains the same compatibility as in upstream Bitcoin.
Thanks to Luke-Jr for raising this issue.
Newer mingw supports the features necessary to enable this api, whereas older
versions didn't. However once enabled (automatically by configure), it triggers
an unrelated build bug.
Since it was not enabled previously anyway, and we don't depend on the
functionality, just disable it across the board.
Duke