-ldl seems to be missing from the Linux rules

[cicicice]

Hi,

I found the project gets stuck "out of the box" on all 3 of OSX, Ubuntu and Centos/Oracle. Clion on Windows runs OK with VS17 and VS19. No progress with OSX libsdl errors yet on my part. It appears that a universal problem on Linux was not linking with libdl, the error being "undefined reference to symbol 'dlclose@@GLIBC_2.2.5'". I am not sure where the -ldl switch has to go in the CMake files, but manually fixing it on Oracle Linux 8 gave me a whole bunch of libpng errors, which turned out to depend on -lpng16 and missing symbolic links for libpng: sudo ln -s /usr/lib64/libpng16.so.16 /usr/lib64/libpng16.so

Again I am not sure what would be the way to "fix" the CMake files for this.