- add true unittest and Fl_String testing
- interface and printout are similar to gtest
without requiring external linkage.
just run `unittest --core`.
- new Fl_String API
- extended API to fl_input_str and fl_password_str
- co-authored-by: Albrecht Schlosser <albrechts.fltk@online.de>
This was necessary because the latest GitHub "runner" image (20221120.1)
includes incompatible image libs (libjpeg, libpng, and zlib). This
caused `fluid-cmd.exe` to fail with error code -1073741511. For further
information please refer to this GitHub Issue:
https://github.com/actions/runner-images/issues/6627
The previous runner version (20221027.1) did not include these libs
and our build used the internal libs and worked.
The fix is to disable the search for system libs in CMake.
Note: this does not explain *why* these libs are incompatible.
