I'm sure it's fine, but the slide was accompanied by a statement of "I don't know much about these, but they exist if you want to do more research." I just haven't had much opportunity to work with open source physics libraries.
Thanks for the links. Though, looks many of them are simply public domain replacements for better known libraries (zlib, libpng, freetype). Are there really places where you can't reasonably use zlib-licensed code?
Where I recommended replacements (stb_*, miniz), it wasn't a licensing issue. The usual libraries have perfectly fine licenses.
zlib is fine, but has all this bulk and complexity to support ridiculous systems...as illustration, miniz provides a drop-in replacement in 300 lines of C code.
libpng fails (and fails in hard-to-understand ways) if you used different build options between what you built and what's on the end-user's system, which means you have to ship your own libpng on Linux.
libjpg and libpng force you to use setjmp(), which is unforgivable.
All of these have dozens of C files and possibly complex build details. The alternatives tend to be a single .c file you drop into your project.