I'm not a programmer either but learning

I do have the source for 52ESR here that almost compiles. After 52ESR, Mozilla switched to using the programming language Rust to build various modules. We have no Rust port, a very big job and it seems that linking with Rust modules needs much more memory then a 32 bit platform has. Even by 45ESR (actually it was worse for a while), linking xul.dll basically requires the full possible address range. Back when I only had 1.5 GBs of ram for a while, I actually crashed the machine due to the swap file filling up. Seems it has a 2GB limit, which I'm sure seemed like a lot in the early 90's.
It's a problem with the new browser as well, along with compiling some of the object files eating tons of memory. Dmik had to cut down the number of jobs for make to stop from running out of memory.
Theoretically, it should be possible to cross compile OS/2 binaries on Linux or even Windows, but once again it would be a big job by a knowledgeable person setting things up.
Eventually this will kill OS/2 as developers use 64bit machines full of memory, less and less will run on 32 bit machines.