SPDX License Identifiers are a more compact / standardized
way of representing file license information.
See: https://spdx.dev/resources/use/#identifiers
This was done with the `ambr` search and replace tool.
ambr --no-parent-ignore --key-from-file --rep-from-file key.txt rep.txt *
Including 'Build/' is unfortunate, but this seems to be what everyone does,
short of creating a symlink/hardlink from /AK/Debug.h to /Build/AK/Debug.h.
This feels like a crutch, but it's a better crutch than having a workaround
that could easily break or corrupt commits (i.e., the symlinks).
* Add SERENITY_ARCH option to CMake for selecting the target toolchain
* Port all build scripts but continue to use i686
* Update GitHub Actions cache to include BuildIt.sh
