Reworking local patches.

Rework patches to match upstream merge request. Squash the autotools
ones into one, add acinclude m4 directory.
Add 'Also=lircd.service' to [Install] in socket file.

Makes 'systemctl enable lircd' enable the socket too. Kudos
Zbigniew Jedrzejewski-Szmek.
Disable/enable lircmd only using systemctl.

Kudos: Zbigniew Jedrzejewski-Szmek.
README.fedora: document setup of new instance.

During review the idea of using a template to run different
instances came up. However, using instances would require to
also have instances in sysconfig, something like
/etc/sysconfig/lirc0  etc. Perhaps too complicated. For now,
document creating a new instance "from scratch" in README.fedora.
daemons/lircd.c: review remark: fix dead code.