sh script is not sh compatible? secretly bash?

[CodeAsm]

After trying a arm64 build, sh resulted into the kernel version subdivision error. might be bash/sh incompatible issue.
after targeting /bin/bash, it worked sort of. first step is to fix SH. crosscompiling comes later.

[CodeAsm]

Richard from discord had the same fault, arm64 again. Some functions needed () and he sourced vars inside the build.sh.

https://stackoverflow.com/a/4732283 might be a proper fix to sh