+# pkg-config
+PKG_PROG_PKG_CONFIG
+# This makes sure pkg.m4 is available.
+m4_pattern_forbid([^_?PKG_[A-Z_]+$],[*** pkg.m4 missing, please install pkg-config])
+
+# ------------------------------------------------------------------------------
+have_manpages=no
+AC_ARG_ENABLE(manpages, AS_HELP_STRING([--disable-man-pages],
+ [do not install man pages]))
+AS_IF([test "x$enable_manpages" != xno], [have_manpages=yes])
+AM_CONDITIONAL(ENABLE_MANPAGES, [test "x$have_manpages" = "xyes"])
+
+# ------------------------------------------------------------------------------
+
+AC_ARG_WITH([systemd],
+ AS_HELP_STRING([--with-systemd], [Enable systemd support.])
+)
+
+AS_IF([test "x$with_systemd" != "xno"],
+ [PKG_CHECK_MODULES(systemd, [libsystemd],
+ [have_systemd=yes], [have_systemd=no])],
+ [have_systemd=no]
+)
+
+AS_IF([test "x$have_systemd" = "xyes"],
+ [AC_MSG_CHECKING([for systemd system unit directory])
+ AC_ARG_WITH([systemdsystemunitdir],
+ AS_HELP_STRING([--with-systemdsystemunitdir=DIR], [Directory for systemd service files]),
+ [], [with_systemdsystemunitdir=$($PKG_CONFIG --variable=systemdsystemunitdir systemd)]
+ )
+
+ AC_SUBST([systemdsystemunitdir], [$with_systemdsystemunitdir])
+
+ if test -n "$systemdsystemunitdir" -a "x$systemdsystemunitdir" != xno; then
+ AC_MSG_RESULT([$systemdsystemunitdir])
+ else
+ AC_MSG_ERROR([not found (try --with-systemdsystemunitdir)])
+ fi
+ ],
+ [AS_IF([test "x$with_systemd" = "xyes"],
+ [AC_MSG_ERROR([Systemd support is enabled but no systemd has been found.])
+ ])
+])
+
+AM_CONDITIONAL(HAVE_SYSTEMD, [test "x$have_systemd" = "xyes"])
+
+# ------------------------------------------------------------------------------
+