Unable to compile c++ project when source list is too large..... jikes?

Dear phoenix,

We need your help. We are in an escalation rewriting our PLC software to PLCnext engineer. We are at the stage where we are limited by adding new sources to our project. If we add one more source file then plcnext build will fail on linking, because we believe, the source list is too long.

If I move the folder containing our c++ project further up in the folder hierarchy (reducing the length of the path for each source file) we can compile and link our *.so file again. 

So we are having a little ticking time bomb at the moment. At some point also with this workaround we'll exceed the limit, which will simply block us from adding new cpp files.

The error we get (is not very helpful):

[cmake]: [ 97%] Linking CXX shared library libYieldstarPlcNext.so
[cmake]: c:/localdata/sdks/3152.09/sysroots/x86_64-pokysdk-mingw32/usr/bin/x86_64-pxc-linux/../../libexec/x86_64-pxc-linux/gcc/x86_64-pxc-linux/9.3.0/real-ld.exe: CMakeFiles/YieldstarPlcNext.dir/intermediate/code/YieldstarPlcNextLibrary.cpp.o: in function `YieldstarPlcNext::YieldstarPlcNextLibrary::YieldstarPlcNextLibrary(Arp::AppDomain&)':
[cmake]: YieldstarPlcNextLibrary.cpp:(.text+0xe6): undefined reference to `Arp::System::Acf::LibraryBase::LibraryBase(Arp::AppDomain&, Arp::BasicVersion const&)'
[cmake]: c:/localdata/sdks/3152.09/sysroots/x86_64-pokysdk-mingw32/usr/bin/x86_64-pxc-linux/../../libexec/x86_64-pxc-linux/gcc/x86_64-pxc-linux/9.3.0/real-ld.exe: CMakeFiles/YieldstarPlcNext.dir/src/YieldstarPlcNextComponent.cpp.o: in function `YieldstarPlcNext::YieldstarPlcNextComponent::YieldstarPlcNextComponent(Arp::System::Acf::IApplication&, Arp::BasicString > const&)':
[cmake]: YieldstarPlcNextComponent.cpp:(.text+0x554): undefined reference to `Arp::System::Acf::ComponentBase::ComponentBase(Arp::System::Acf::IApplication&, Arp::System::Acf::ILibrary&, Arp::BasicString > const&, Arp::System::Acf::ComponentCategory, unsigned int, bool)'
[cmake]: c:/localdata/sdks/3152.09/sysroots/x86_64-pokysdk-mingw32/usr/bin/x86_64-pxc-linux/../../libexec/x86_64-pxc-linux/gcc/x86_64-pxc-linux/9.3.0/real-ld.exe: CMakeFiles/YieldstarPlcNext.dir/src/YieldstarPlcNextComponent.cpp.o:(.data.rel.ro._ZTVN16YieldstarPlcNext25YieldstarPlcNextComponentE[_ZT

It looks like this is on Windows.
Are you building this project in Eclipse, or in Visual Studio, or on the command line?
It looks like it could be something like this issue:
Solving the 8192 Character Command Line Limit on Windows | MCU on Eclipse
… which would be a general Windows issue, not necessarily specific to the PLCnext Toolchain.
If you’re not using Visual Studio, can you try building the project on a Linux machine, and see if it has the same problem there?