build: assume we have at least systemd v200

systemd v200 was released over 10 years ago.
It is thus reasonable to no longer support versions older than that and
simplify the build system a bit.

Makefile.am

@@ -5554,13 +5554,8 @@ systemdsystemunit_DATA += \
 data/NetworkManager.service: $(srcdir)/data/NetworkManager.service.in
 	$(AM_V_GEN) $(data_edit) $< >$@
 
-if HAVE_SYSTEMD_200
 data/NetworkManager-wait-online.service: $(srcdir)/data/NetworkManager-wait-online.service.in
 	$(AM_V_GEN) $(data_edit) $< >$@
-else
-data/NetworkManager-wait-online.service: $(srcdir)/data/NetworkManager-wait-online-systemd-pre200.service.in
-	$(AM_V_GEN) $(data_edit) $< >$@
-endif
 
 data/NetworkManager-dispatcher.service: $(srcdir)/data/NetworkManager-dispatcher.service.in
 	$(AM_V_GEN) $(data_edit) $< >$@

configure.ac

@@ -334,9 +334,6 @@ if test "$with_systemdsystemunitdir" != no; then
 	AC_SUBST([systemdsystemunitdir], [$with_systemdsystemunitdir])
 fi
 
-PKG_CHECK_MODULES(SYSTEMD_200, [systemd >= 200], [have_systemd_200=yes], [have_systemd_200=no])
-AM_CONDITIONAL(HAVE_SYSTEMD_200, test "${have_systemd_200}" = "yes")
-
 # Hostname persist mode
 AC_ARG_WITH(hostname-persist,
             AS_HELP_STRING([--with-hostname-persist=default|suse|gentoo|slackware],

data/NetworkManager-wait-online-systemd-pre200.service.in

@@ -1,15 +0,0 @@
-[Unit]
-Description=Network Manager Wait Online
-Documentation=man:nm-online(1)
-Requisite=NetworkManager.service
-After=NetworkManager.service
-Wants=network.target
-Before=network.target
-
-[Service]
-Type=oneshot
-ExecStart=@bindir@/nm-online -s -q --timeout=30
-RemainAfterExit=yes
-
-[Install]
-WantedBy=network.target

data/meson.build

@@ -12,14 +12,9 @@ if install_systemdunitdir
     'NetworkManager-dispatcher.service.in',
     'NetworkManager.service.in',
     'nm-priv-helper.service.in',
+    'NetworkManager-wait-online.service.in',
   ]
 
-  if have_systemd_200
-    services += ['NetworkManager-wait-online.service.in']
-  else
-    services += ['NetworkManager-wait-online-systemd-pre200.service.in']
-  endif
-
   foreach service: services
     configure_file(
       input: service,

meson.build

@@ -273,7 +273,6 @@ libsystemd_login_dep = dependency('libsystemd-login', version: '>= 183', require
 config_h.set10('HAVE_LIBSYSTEMD', libsystemd_dep.found())
 
 systemd_dep = dependency('systemd', required: false)
-have_systemd_200 = systemd_dep.found() and systemd_dep.version().version_compare('>= 200')
 
 gio_unix_dep = dependency('gio-unix-2.0', version: '>= 2.40')