japanese/eb: Add patch to fix buffer overrun in eb/multiplex.c

While I'm here,

• Pet portlint and portclippy
• Tidy up Makefile with portfmt

Reported by: Kazuhiro Ito
Obtained from: edict ML <edict@ring.gr.jp>
MFH: 2022Q2
Security: 17a30a24-c579-11ec-bbbd-0800270512f4

(cherry picked from commit 2140f32d458610dd076b00670a68def3b7f39d37)