sh(1): add -l option

[bapt]

Summary

-l is required by LSB for login shell, all other shells: bash, zsh,
oksh, mksh, ... implements it.

with -l sh will act as a login shell and read the profile.

Obtained From: dash (3b7c8442bfe7c2fd0a6b0415df6ddf66a399fd55)

[bapt]

add missing manpage change

[kib]

bin/sh/options.c

86