- Fix patch patch handle-numlock-value-in-etc-sysconfig-keyboard.patch
that is do not close a file descriptor twice (boo#973907)

- Add two patches which address logind/networkd disappearing from
dbus (and busctl) even while the units and processes continue
running.
0001-core-fix-bus-name-synchronization-after-daemon-reloa.patch
0001-core-re-sync-bus-name-list-after-deserializing-durin.patch

- drop all compiler/linker option customizations:
- -pipe option is used by default since day 0
- get rid of cflags() function which is not needed
- --hash-size has no impact specially in runtime
IOW, use the default options for the compiler and the linker,
there's no point in making systemd different from other package in
this regards.

- use %make_build instead of 'make %{?_smp_mflags}'

- be more strict on own lib version requirements

- systemd should require udev with the exact same version

- Modify patch handle-numlock-value-in-etc-sysconfig-keyboard.patch
to allow that open, seek, and read of /dev/mem may fail e.g.
on XEN based virtual guests (bsc#961120)

- require curl and bzip2 to build importd
- curl also causes building of journal-upload. That one has rather
unusal certificate usage, set it's ca root to /etc/pki/systemd