sorry this is old source code i fixed the static build options in the qt.pro file but apparently it was missing in the makefile.mingw aswell im recompiling now ill update the links above shortly and create another pull request on github to fix these for others that wish to compile from source
EDIT
ok try with out it first with new compile here https://mega.nz/#!F1EinSAB!ammmINp-ki2qVfxq03VlCq60zbtYastLG-Rpx3wEL5E
heres url to the libwinpthread i built it with if the above doesnt work wihtout it just put it in the same folder as the wallet-qt
https://mega.nz/#!t4VQ1DjQ!XYALDZ6ZYC4tKCzS4734XZwTUWlwBsjGI3geyoTfp4c
Newest compile is still throwing the dll error. I would just package them together for now until you get it fixed.