This fork generates copies of the golang.org/x/sys/unix package source files that would be
used for linux/arm64 and changes their build tags to js/wasm, allowing libraries using golang.org/x/sys/unix (often assuming Linux) to build for wasm.
It also does something similar for the syscall standard library, and replaces
imports in the generated source added to unix with the generated wasm/syscall package here.
After generating, both have been tuned by hand to sub out empty function bodies, replace internal imports, etc until things compile.
At this point, there is no way to hook into replace stubbed syscalls, but they are at least defined and programs will compile.