C++11 requirement conflict with the latest casacore version

[rvweeren]

It seems that doing a dysco install with cmake is not compatible anymore with the latest casacore due to the C++11 requirement here:

https://github.com/aroffringa/dysco/blob/c682fe5987cdc8514eca79f33d55837f08213172/CMakeLists.txt#L19C22-L19C27

Using this
cmake -Wno-dev -DCMAKE_INSTALL_PREFIX=/opt/lofar/dysco -DCASACORE_ROOT_DIR=/opt/lofar/casacore -DTARGET_CPU=cascadelake -DPORTABLE=False ../src

you get the these sort of errors (related to the old C+11 standard)

/opt/lofar/casacore/include/casacore/casa/Utilities/DataType.h: In function 'constexpr size_t casacore::SizeOfType(DataType)':
/opt/lofar/casacore/include/casacore/casa/Utilities/DataType.h:265:1: error: body of 'constexpr' function 'constexpr size_t casacore::SizeOfType(DataType)' not a return-statement
  265 | }

[aroffringa]

If you use the latest casacore, Dysco is part of casacore, so you don't need to install Dysco separately. The separate Dysco install is only necessary for older versions of Casacore.