Allow for recursive mutex on Windows
Allow for recursive mutex on Windows

Signed-off-by: Martin Sustrik <4dd6061be1198639e8b05ce4fd5ead7a0dcaa0f4@250bpm.com>

potatogim/nanomsg,TTimo/nanomsg,ttyangf/nanomsg,nirs/nanomsg,imp/nanomsg,snikulov/nanomsg,wfxiang08/nanomsg,ttyangf/nanomsg,kaostao/nanomsg,imp/nanomsg,TTimo/nanomsg,modulexcite/nanomsg,thisco-de/nanomsg,hyperfact/nanomsg,smithed/nanomsg,reqshark/nanomsg,krafczyk/nanomsg,TTimo/nanomsg,pakozm/nanomsg,gdamore/mamomsg,featherweight/ftw-kernel-nanomsg,smithed/nanomsg,gdamore/mamomsg,zerotacg/nanomsg,krafczyk/nanomsg,zerotacg/nanomsg,yan97ao/nanomsg,kaostao/nanomsg,hyperfact/nanomsg,gdamore/mamomsg,wirebirdlabs/featherweight-nanomsg,reqshark/nanomsg,kaostao/nanomsg,snikulov/nanomsg,modulexcite/nanomsg,thisco-de/nanomsg,ttyangf/nanomsg,krafczyk/nanomsg,wfxiang08/nanomsg,cosin2008/nanomsg.NET,cosin2008/nanomsg.NET,nirs/nanomsg,simplestbest/nanomsg,zerotacg/nanomsg,imp/nanomsg,JackDunaway/featherweight-nanomsg,tempbottle/nanomsg,smithed/nanomsg,JackDunaway/featherweight-nanomsg,nirs/nanomsg,hyperfact/nanomsg,linearregression/nanomsg,featherweight/ftw-kernel-nanomsg,reqshark/nanomsg,linearregression/nanomsg,simplestbest/nanomsg,wirebirdlabs/featherweight-nanomsg,pch957/nanomsg,kaostao/nanomsg,tempbottle/nanomsg,ttyangf/nanomsg,pakozm/nanomsg,simplestbest/nanomsg,potatogim/nanomsg,pch957/nanomsg,cosin2008/nanomsg.NET,pakozm/nanomsg,pch957/nanomsg,linearregression/nanomsg,wfxiang08/nanomsg,smithed/nanomsg,wirebirdlabs/featherweight-nanomsg,yan97ao/nanomsg,potatogim/nanomsg,TTimo/nanomsg,modulexcite/nanomsg,yan97ao/nanomsg,tempbottle/nanomsg,JackDunaway/featherweight-nanomsg