ref: 3bf2f2e262eebfcc1699d45f6717ae6a07cb32a7
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#
}