Trying to fix Visual Studio 2013 lack of constexpr.

6 jobs for c++11_matrix in 36 minutes and 23 seconds
Status Name Job ID Coverage
  Test
passed clang-c++11-Qt5 #14209
Linux MultiThreads

00:08:57

passed cppcheck #14210
Linux MultiThreads

00:36:22

passed gcc-c++11-Qt5 #14208
Linux

00:03:26

failed VS2013-Qt-5.5.1-x64 #14213
VS2013 Qt551

00:12:54

passed VS2015-Qt-5.6.0-x32 #14212
VS2015 Qt56

00:18:08

passed VS2015-Qt-5.6.0-x64 #14211
VS2015 Qt56

00:22:12

 
Name Stage Failure
failed
VS2013-Qt-5.5.1-x64 Test There is an unknown failure, please try again
173>CustomBuild:
173> Building Custom Rule E:/gitlab/builds/7949bd93/0/OpenFlipper-Free/OpenFlipper-Free/CMakeLists.txt
173> CMake does not need to re-run because E:\gitlab\builds\7949bd93\0\OpenFlipper-Free\OpenFlipper-Free\rel\CMakeFiles\generate.stamp is up-to-date.
173>
173>Build succeeded.
173>
173>Time Elapsed 00:00:00.24
========== Build: 74 succeeded, 99 failed, 0 up-to-date, 0 skipped ==========
ERROR: Build failed: exit status 1