Dependences for cross-platform builds

[Kriper1111]

Certain dependencies aren't available on all platforms out of the box:

• cddlib isn't available on vcpkg for Windows and is a PITA to compile.
• imgui isn't available on brew for MacOS, but could be built from sources (include their repo as a submodule)
• GLAD isn't really available anywhere, but could be included in the repo manually, as it was.

Needs to find the substitutes/alternatives, if we want GitHub Actions CI.

[Kriper1111]

Completely forgot about the quickhull lib I use and it's unlikely to be available from any of the major package lists. So there goes the first submodule, ImGui is likely to follow, as this Makefile relies on my dev layout, which builds it from source.. which isn't included in the repo. Oops.

[Kriper1111]

Couple of updates: ImGui is now being uncached from source on Linux, forgot to add that on Windows runner.

The biggest headache is, as always, Microsoft and its vcpkg, god damn the thing. I'll probably end up using precompiled glfw/glm or building the former from source on Windows, as Linux doesn't have too much issues with that.

[Kriper1111]

So now that builds are a thing, it's time to think about cddlib on Windows.
Also need to "runtest" assets baking before I can comfortably close this issue. (#9)

[Kriper1111]

Who would've thunk that actually reading a suggestion from the tool might help.
I've managed to configure cddlib with --disable-dependency-tracking, as it suggested me to do in the first place. I hope that the github runner has make, but I'd much rather build it from Visual Studio builder, as the main part of code is being built this way already.

No real harm in changing the builder, but consistency.
I have managed to produce a working example though. It would require modifying the config.h fallback for Makefile, as it's clashing with cmake's config. Could probably just use the add_dependency command in the file, although it's not the best approach I'd reckon.

[Kriper1111]

..well that didn't work.
Who would've thunk that autotools are thorough enough to expand /bin/sh to its full install path.
Which may include spaces. Which they cannot handle. Nice.

A few fixes are underway -- I'll look into sed-ing the configured Makefiles to quote out the $(SHELL) to "$(SHELL)" and am also working on a quickie CMake port of cddlib's toolchain. I'd have to look into how it's best published.

[Kriper1111]

I don't like cddlib.

[Kriper1111]

In other words, it is somewhat inconsistent with where are its headers located across focal and jammy versions of it.
That's the problem with it on Linux runner.
On Windows runner the problem is that they use autotools. I'll probably either regress to an older fork with cmake compat or make my own. Mixing compilers is heresy.