Update FindCImg.cmake

[Neumann-A]

a) You probably want to use (builtin) FindThreads.cmake instead some not existing FindPTHREAD.cmake

b) You probably want to use just find_library for GDI instead of some not existing FindGDI.cmake

[jkriege2]

Hi!

That are some unfortunate errors that did not come up so far due to problems with the Appveyor-build (it didn't build the CImag examples on Ubuntu) and due to the fact that I'm working solely on windows.

It seems there are two parts to this:

1. The PTHreads-fix should be fine,
2. BUT the GDI-fix does not really work ... I think I will rework this to do it the same way, it is done in the examples for CImg: https://github.com/GreycLab/CImg/blob/master/examples/CMakeLists.txt ...

If you like, could you change the PR to match the CMakeLists.txt given above ... or remove the GDI-part and I will do that part myself (and I will merge the PThreads part).

Thanks for the PR anyways,
JAN

[Neumann-A]

Let me just quickly remove gdi32 completely since it should be automatically linked in by CMake (via CMAKE_<LANG>_STANDARD_LIBRARIES)

https://gitlab.kitware.com/cmake/cmake/-/blob/master/Modules/Platform/Windows-GNU.cmake?ref_type=heads#L47
https://gitlab.kitware.com/cmake/cmake/-/blob/master/Modules/Platform/Windows-MSVC.cmake?ref_type=heads#L226

[jkriege2]

Hi!

I just fixed the appveyor build-scripts in master to actually build with CImg on Ubuntu ... COuld you rebase your PR, which should also rerun the CI? Then we see whether the changes worked!

Best,
JAN