* Update BUILDING.md
```
Package vulkan-validationlayers-dev is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source
However the following packages replace it:
vulkan-utility-libraries-dev
```
on Ubuntu 24 LTS installing ``` vulkan-utility-libraries-dev``` seems to fix the problem
* removed vulkan-validationlayers
* Update BUILDING.md
---------
Co-authored-by: DHrpcs3 <dh.rpcs3@gmail.com>
Third party dependencies have been merged into the source tree as submodules! If you previously installed RPCSX when you needed `spirv-cross`, `gslang`, or `xbyak`, you should run:
```
git pull
git submodule update --recursive --remote
```
This removes the second way for arch to install spriv-cross as its easier / better to just use YAY.
This also fixes the warning to make it an actual warning and stand out a bit more.
