Introduce generic host config and related helpers

Add generic host config struct and related helpers for TCP-based probes
and use them for ctrl probe.

This will be used in follow-up patch for OpenVPN probe as well.

Change-Id: Ie321655a92cdbefbfaa056ac0d583397c83beccb
diff --git a/src/Makefile.am b/src/Makefile.am
index d0d6a22..f639023 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -21,7 +21,7 @@
 	$(NULL)
 
 noinst_LTLIBRARIES = libintern.la
-libintern_la_SOURCES = simple_ctrl.c
+libintern_la_SOURCES = simple_ctrl.c client.c
 libintern_la_LIBADD = $(LIBOSMOCORE_LIBS) $(LIBOSMOGSM_LIBS)
 
 osmo_sysmon_CFLAGS = $(LIBMNL_CFLAGS) $(LIBOSMOVTY_CFLAGS) $(LIBOPING_CFLAGS) $(AM_CFLAGS)
@@ -44,6 +44,7 @@
 
 noinst_HEADERS = \
 	osysmon.h \
+	client.h \
 	simple_ctrl.h \
 	value_node.h \
 	$(NULL)