RE: ARM UPDATE --
I tried to compile the latest source on my 8GB Rpi 4, utilizing the ARM build script. It failed with an error pointing to line 1247. The line instruction "-flex-vector-conversions" was in the ARM build script CFLAGS portion, so I did not edit that script, I just ran it.
I can run the build and log the entire thing in a text file, or just cut-n-paste the final error details, then pass the log to you in an email, zipped. Let me know what you might want. --scryptr