Support for newer glslang versions without SPIRV and HLSL libraries

[keithbowes]

Description

This makes it so that RetroArch can be compiled with glslang 14+, which have removed the separate HLSL library. Currently, the SPIRV library is an empty stub in glslang 14/15 but the indicated plan is to eventually remove that too, so I've followed suit.

Related Issues

Fixes #16571

[LibretroAdmin]

I'm kinda wary of this. Will this have any impact for the D3D drivers when using Slang shaders?

[keithbowes]

No idea, but I was just checking back now that glslang 15.2.0 has been released with SPIRV removed. I had to recompile RetroArch because it complained that it couldn't find libSPIRV.so.15. I'm on a new computer and so would have to install MinGW stuff in order to test in Windows, but I don't see why it wouldn't work; the HLSL and SPIRV functionality is still there, but in the glslang library instead of in separate libraries. With this PR, the configure script still checks for those libraries and uses them if the system has them, but if the system doesn't, it doesn't produce an error (similarly to what happened with OSDependent and OGLCompiler when they were removed).