[Development] Qt git 5.7 + MSYS2 + lrelease

[Massimo Callegari]

Hi all,
I have finally been able to produce the first qt5-git (5.7 branch) package with MSYS2, including libraries, executables, examples, tools and docs. 
For all the submodules except for qtscxml.
I believe it is a very nice one-command automation for who doesn't want to bother with long and complicated setups.

However, when processing qttranslations, I realized the lrelease.exe executable is not right. It fails on the first .ts file with this error:

/D/MINGW-packages/mingw-w64-qt5-git/src/qt5/qttranslations/translations/lrelease_wrapper.sh assistant_cs.ts -qm assistant_cs.qm 

This application has requested the Runtime to terminate it in an unusual way. 
Please contact the application's support team for more information. 
terminate called after throwing an instance of 'std::ios_base::failure' 
what():  basic_ios::clear

I am wondering if anyone has seen this before and can help.
I am not able to tell (yet) if this depends on GCC 5.3.0 or the Qt c++11 ongoing porting.

Any advise appreciated.

Thanks and regards,
Massimo