Bug#1013298: O: flycheck -- modern on-the-fly syntax checking for Emacs

[Manphiz]

control: tags -1 patch

After discussing on IRC and with permission from anarcat, I intend to
adopt flycheck.  An MR is being prepared at [1].

[1] https://salsa.debian.org/emacsen-team/flycheck/-/merge_requests/3
-- 
Manphiz