My apologies for the delay! I've attached to this comment my (now somewhat heavily modified, formatted, e.t.c) version of (most of) the repo. I noticed a variety of places that the original author had been specifying alignments that would definitely only work on 32-bit, as well as various places where they were assuming the size of a pointer was always 4 bytes (whereas it's of course 8 on 64-bit systems), so I thought I'd take the time to correct that as well and add a bunch of ifdefs to fully account for 32 vs 64 bit in various areas the best I could.
I also added a few extra command line options to it (you can now specify -Sys specifically for the system unit, so that it won't try to load the system unit, for one.)
Note that overall I've found the code generator for this compiler is rather more advanced than the understanding its parser currently has of Pascal (which is better than the reverse of that, I'd say.) There are a number of things that should in theory compile (at the Pascal level, not the LLVM level) but don't.
As to the "LLVM level", secondly note that I've commented out all the code that inserts exception handling stuff into methods, as I just didn't have the time to fully update all of that in a cross-platform way, and it would not compile in LLVM versions higher than 3.7.
I will say though that again the code generator is definitely sufficiently advanced enough with a solid enough foundation to be a good platform for additional work, whether that means by attaching it to a better parser (FCL-Passrc perhaps?) or by simply finishing/improving the existing one.