Emscripten for Qt fails build.

[enivak]

I am trying to add zeromq qt for emscripten. Unfortunately i failed to complete the build steps. I got an error of ```
Running configuration tests...
Checking for valid makespec... Note: Also available for Linux: linux-clang linux-icc

ERROR: Cannot compile a minimal program. The toolchain or QMakeSpec is broken.

Check config.log for details.

[sneubert]

Hi enivak, please show us your config.log.