ref: f6aa1954f1076821fe2cd8f34df9fceaf1f5c53a
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#
}