We do. I always use fasmg and it's amazing!!
replyfasmg[12] is much more powerful than gas or nasm(~yasm): it is not a classic pre-processor. With CALM, it is basically a language able to implement assemblers supporting various binary file formats.
replyThe pre-processor of an assembler is specific to that very assembler.
replyFor instance, with a C pre-processor, I have a very lean C pre-processor dialect which allows me to assemble simple x86_64 code with... fasmg[12] or nasm(probably yasm) or gas(intel syntax).
A big project which was bitten by specific pre-processor abuse: ffmpeg with nasm (but it is still much less toxic than to start to be hard dependent on advanced and specific C compiler extensions... look a the failure from linux on that matter).