with the gpg4win-4.2.0 release I had trouble again because of different thread implementations used which apparently caused some kind of c++ ABI break when the okular pdf "plugin" was loaded. With std::async in c++11 its a bit of a mess with the different implementations.
Since ~6 months all my development builds of Gpg4win use the equivalent of debians i686-w64-mingw32-gcc-posix the only disadvantage I saw was that the 64bit binaries from us also have a dependency on libwinpthreads.dll but otherwise we already ship it for x86 since some of our parts require it explicitly (even GPGME afaik)
This is only for Gpg4win, so not for the critical parts like gcrypt / gnupg / npth etc.
I just wanted to note this down as a ticket so that its not forgotten before the next release.