Windows: Configure fails due to clang-cl support

Configuring Qt 5.7 on Windows does not work since the intial clang-cl support has been added (https://codereview.qt-project.org/#/c/145351/).

Option -platform win32-msvc2013 is passed to the configure script however the configure.bat finds clang-cl.exe and use it instead of the msvc compiler. The clang-cl.exe (version 3.6.2) is installed by Qt Creator 3.5.1 and I'm not intended to use it.

The attached configure.log files contains the complete option list passed to the configure script and the error messages.