Labplot master branch build failures

[Rik Mills]

Restoring:

#include <cmath>
in src/backend/core/AbstractColumn.h

&

#include <QVector>
in  src/backend/matrix/MatrixPrivate.h

https://paste.kde.org/phftxuwzm

superficially at least, fixes the build for me.

My C++ and familiarity with this code is a little bit too flaky to
comment on whether this is ok in other respects.

Thanks

On 13/06/17 10:01, Rik Mills wrote:
> Bisecting locally building with GCC6, culprit or 1st bad commit seems to be:
> 
> https://cgit.kde.org/labplot.git/commit/?id=d220081a978788c67ea99749c4c56176aaa2a7a1
> 
> On 13/06/17 09:41, Rik Mills wrote:
>> Seems to fail with GCC 6, but succeeds with GCC 5.
>>
>> Failures on GCC6:
>>
>> artful http://kci.pangea.pub/job/artful_unstable_labplot/45/
>> zesty http://kci.pangea.pub/job/zesty_unstable_labplot/52/
>>
>> make[3]: *** [src/CMakeFiles/labplot2.dir/kdefrontend/GuiObserver.cpp.o]
>> Error 1
>> make[3]: *** Waiting for unfinished jobs....
>> In file included from
>> /<<BUILDDIR>>/labplot-2.4.0+p17.10+git20170613.0754/src/backend/spreadsheet/Spreadsheet.h:33:0,
>>                  from
>> /<<BUILDDIR>>/labplot-2.4.0+p17.10+git20170613.0754/src/kdefrontend/MainWin.cpp:36:
>> /<<BUILDDIR>>/labplot-2.4.0+p17.10+git20170613.0754/src/backend/core/column/Column.h:
>> In constructor ‘Column::ColumnStatistics::ColumnStatistics()’:
>> /<<BUILDDIR>>/labplot-2.4.0+p17.10+git20170613.0754/src/backend/core/column/Column.h:46:15:
>> error: ‘NAN’ was not declared in this scope
>>      minimum = NAN;
>>                ^~~
>> src/CMakeFiles/labplot2.dir/build.make:372: recipe for target
>> 'src/CMakeFiles/labplot2.dir/kdefrontend/MainWin.cpp.o' failed
>>
>> Success on GCC 5:
>>
>> xenial KCI http://kci.pangea.pub/job/xenial_unstable_labplot/55/
>>
>> and for ref on other CI using GCC5
>>
>> xenial NCI
>> http://build.neon.kde.org/job/xenial_unstable_kde-extras_labplot/41/
>> KDE CI https://build.kde.org/job/labplot%20master%20kf5-qt5/180/
>>
>