Mod for C++14 +

[jaggzh]

..../djcodecd.cc:26:
/usr/include/dcmtk/config/osconfig.h:1145:2: error: invalid preprocessing directive #errorDCMTK
1145 | #error\
| ^~~~~~
1146 | DCMTK was configured to use C++14 features, but your compiler does not or was not configured to provide them. cmake_minimum_required(VERSION 3.12)

I actually had to go to v17 to get it to build.

In CMakeLists.txt:
Change:
set (CMAKE_CXX_STANDARD 11)
To:
set (CMAKE_CXX_STANDARD 17)