ref: caa2cd99e469f598d19a03f2ba4d3c23c6e9d6f5
dir: /lib/std/sljoin.myr/
use "alloc"
use "slcp"
pkg std =
generic sljoin : (dst : @a[:], src : @a[:] -> @a[:])
;;
generic sljoin = {dst, src
var len
len = dst.len
dst = slgrow(dst, len + src.len)
slcp(dst[len:], src)
-> dst
}