ref: 5e2dccff3e46d063fed04109f5088c16002a56f5
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
	slgrow(dst, len + src.len)
	slcp(dst#[len:], src)
	-> dst#
}