I have a TrueOS installation. I was wondering if it was possible to follow the LFS book on my current system.
No.
If you want to cross-compile a Linux-based operating system from a non-Linux-based operating system, you are out of luck with the Linux From Scratch doco, which explicitly states as its base requirement that you already have and are using a Linux-based operating system with a particular flavour of tools. The build processes rely upon the idiosyncrasies of GNU tools and compilers, starting from GNU makefiles and including that the (second) project to make Linux buildable with the clang compiler has not yet succeeded.
If you want to build a FreeBSD or Project Trident operating system, the Linux From Scratch doco is the wrong thing to be looking at, because it is about entirely the wrong operating system. Project Trident systems are built with different toolchains, and in different ways. Different even to the way that TrueOS and FreeBSD systems are built, which are in their turn different to the way that Linux-based operating systems are built, not the least of which is in the use of ZFS cloning and boot environments.
Further reading
- "Host System Requirements". Linux From Scratch.
- https://github.com/ClangBuiltLinux/linux/wiki
- Is it possible to compile a full Linux system with Intel's compiler instead of GCC?
- Is there a Linux distro compiled with clang/llvm?
- "Updating and Upgrading FreeBSD". FreeBSD Handbook.
- Matthew Seaman (2012). Using ZFS for Managing FreeBSD System Updates. infracaninophile.
- https://github.com/trueos/trueos
- https://github.com/project-trident/trident-build